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بررسی اتصال فاز مایع گذرا فولاد زنگ نزن AISI 304L با ریزساختارهای آستنیتی و مارتنزیتی Transient liquid phase bonding of AISI 304L stainless steels with the austenitic and martensitic microstructures 1 1 در این پژوهش به بررسی تاثیر زمان و ساختار فلز پایه بر ریزساختار منطقه اتصال فاز مایع گذرای فولاد زنگ نزن L304 پرداخته شده است. اتصال فاز مایع گذرا در دمای  °C1050 در دو زمان 5 و 60 دقیقه بر روی فلزات پایه با دو ساختار آستنیت درشت دانه و مارتنزیتی و با لایه واسط BNi-2 انجام گرفت. جهت ایجاد ساختار تمام مارتنزیتی، نمونه های فولاد زنگ نزن L 304 اولیه در دمای  °C15- تا 80% نورد سرد شد. بررسی های میکروسکوپی نشان داد که در زمان 5 دقیقه، در ناحیه اتصال دو منطقه انجماد همدما و انجماد غیرهمدما به وجود آمده است. ناحیه انجماد همدما دارای ساختار تکفاز γ و منطقه انجماد غیرهمدما دارای ساختار چندفازی پیچیده ای بود. این در حالی است که پس از 60 دقیقه، تمام ساختار اتصال به صورت همدما انجماد یافته بود و اتصالاتی عاری از عیب حاصل شد. نتایج همچنین نشان داد که ساختار مارتنزیتی فلز پایه که البته در حین سیکل حرارتی جوشکاری به آستنیت فوق ریزدانه بازگشت می یابد تاثیر قابل ملاحظه ای بر عرض ناحیه متاثر از نفوذ داشته است. 2 In the present study, the effect of time and base metal microstructure on the Transient Liquid Phase (TLP) bonding of 304L stainless steel was studied. TLP was performed at 1050 0C for 5 and 60 minutes on the coarse grain austenitic and martensitic microstructure using BNi-2 interlayer. To prepare martensitic microstructure, as-received 304L was rolled at -15 0C up to 80% rolling reduction. TEM analysis was proved that the microstructure of 80% rolled samples consisted of two different morphologies of martensite namely as lath-type and dislocation cell type martensite.  It was observed that the structure of bonded zone after 5 min has consisted of isothermally solidified zone (ISZ) containing γ solid solution and athermally solidified zone (ASZ) containing complex boride phases. Meanwhile, after 60 min of  heating, the structure of bonded zone completely solidifies isothermally. The obtained results also showed that the martensitic microstructure considerably effect on the width of diffusion affected zone (DAZ) which was related to the reversion of martensite to ultrafine grain austenite during heating. 1 11 2017/06/8 1396/3/18 2018/12/6 1397/9/15 سینا قادری S. Ghaderi دانشکده مهندسی مواد، دانشگاه صنعتی اصفهان. Iran فتح اله کریم زاده F. Karimzadeh دانشکده مهندسی مواد، دانشگاه صنعتی اصفهان. ایران علی اشرفی A. Ashrafi دانشکده مهندسی مواد، دانشگاه صنعتی اصفهان. ایران AISI 304L stainless steel Transient liquid phase bonding Diffusion Isothermal solidification Diffusion affected zone. فولاد زنگ نزن304L اتصال فاز مایع گذرا نفوذ انجماد همدما ناحیه متاثر از نفوذ. ##[1] Lippold J.C., Kotecki D.J., Welding metallurgy and weldability of stainless steels, John Wiley, New York. 2005.##[2] MacDonald W.D., Eagar T.W., “Isothermal Solidification Kinetics of Diffusion Brazing”, Metallurgical and Materials Transactions A, Vol. 29A, pp. 315-325, 1998.##[3] Abdolvand R., Atapor M., Shamanian M., Allafchian A., “The effect of bonding time on the microstructure and mechanicalproperties of transient liquid phase bonding between SAF 2507 andAISI 304”, Journal of Manufacturing Processes, Vol. 25, pp. 172-180, 2017.##[4] Padron T., Khan T.I., Kabir M.J., “Modelling the transient liquid phase bonding behaviour of a duplex stainless steel using copper interlayers”, Materials Science and Engineering A, Vol. 385, pp. 220-228, 2004.##[5] Duvall D.S., Owczarski W.A., Paulonis D.F., “TLP Bonding: a New Method for Joining Heat Resistant Alloys”, Welding Journal, Vol. 53, pp. 203-214, 1974.##[6] Luozzo N.D., Fontana M., Arcondo B., “Transient liquid phase bonding of steel using an Fe–B interlayer”, Materials Science,Vol. 42, pp. 4044-4050, 2007.##[7] Arafin M.A., Medraj M., Turner D.P., Bocher P., “Effect of alloying elements on the isothermal solidification during TLP bonding of SS 410 and SS 321 using a BNi-2 interlayer”, Materials Chemistry and Physics, Vol. 106, pp. 109-119, 2007.##[8] Kuntz M.L., Zhou Y., Corbin S.F., “A Study of Transient Liquid-Phase Bonding of Ag-Cu Using Differential Scanning Calorimetry”, MetallurgicalandMaterials Transactions A, Vol. 37, pp. 2493-2504, 2006.##[9] Gale W.F., Wallach E.R., “Microstructural Development in Transient Liquid-Phase Bonding”, Metallurgical Transactions A, Vol. 22A, pp. 2451-2457, 1991.##[10] Garcia H.M.H., Martinez A.I., Arroyo R.M., Davila J.L.A., Vazquez F.G., Valdes F.A.R., “Effects of Silicon Nanoparticles on the Transient Liquid Phase Bonding of 304 Stainless Steel”, Materials Science & Technology, Vol. 30, pp. 259-262, 2014.##[11] Atabaki M.M., Wati J.N., Idris J., “Transient Liquid Phase Diffusion Brazing of Stainless Steel 304”, Welding Journal, Vol. 92, pp. 57-63, 2013.##[12] Sadeghian M., Ekrami A., Jamshidi R., “Transient liquid phase bonding of 304 stainless steel using Co-base interlayer”, Science and Technology of Welding and Joining, DOI: 10.1080/13621718.2017.1302180, 2017. ##[13] Sabooni S., Karimzadeh F., Enayati M.H., Ngan A.H.W., “The Role of Martensitic Transformation on Bimodal Grain Structure in Ultrafine Grained AISI 304L Stainless Steel”, Materials Science & Engineering A, Vol. 636, pp. 221-230, 2015.##[14] American Welding Society, Specification for Filler Metals for Brazing and Braze Welding, 1998.##[15] Pouranvari M., Ekrami A., Kokabi A.H., “Solidification and Solid State Phenomena During TLP Bonding of IN718 Superalloy Using Ni–Si–B Ternary Filler Alloy”, Journal of Alloys and Compounds, Vol. 563, pp. 143-149, 2013.##[16] Pouranvari M., Ekrami A., Kokabi A.H., “Transient Liquid Phase Bonding of Wrought IN718 Nickel Based Superalloy Using Standard Heat Treatment Cycles: Microstructure and Mechanical Properties”, Materials and Design, Vol. 50, pp. 694-701, 2013. ##

کمینه‌سازی اعوجاج ناشی از جوشکاری، با استفاده از توالی بهینه در یک پانل بزرگ فولادی Minimizing distortion caused by welding, by sequencing optimization in a large steel panel 1 1 جوشکاری به طور گسترده ای در صنایع برای مونتاژ محصولات مختلف مانند کشتی، اتومبیل، قطار و پل استفاده می شود. اعوجاج جوش اغلب نتایجی مانند عدم دقت ابعادی در طول مونتاژ و افزایش هزینه های ساخت را درپی دارد. بنابراین، پیش‌بینی و کاهش اعوجاج جوش برای بهبود کیفیت سازه جوش داده شده بسیار مهم است. در این مطالعه پیش‌بینی اعوجاج ابتدا با استفاده ترکیب آنالیز المان محدود حرارتی الاستیک – پلاستیک و روش الاستیک که بر اساس تئوری تغییرشکل‌های ذاتی است، توسعه داده شد. پس از آن تغییرشکل‌های ذاتی اتصالات جوشی در طول پروسه جوشکاری پانل بزرگ بدست آمد و خصوصیات آن مورد بررسی قرار گرفت. پس از بدست آوردن تغییرشکل‌های ذاتی از روش سودمند الاستیک جهت آنالیز اعوجاج پانل بزرگ استفاده شد. در نهایت تاثیر ترتیب جوشکاری بر روی اعوجاج پانل بزرگ بررسی شد. نتایج آنالیز الاستیک اعوجاج‌هایی را در لبه‌های پانل و مناطق داخلی آن نشان داد، که با تغییر ترتیب جوشکاری تقویتی‌های پانل به یک ترتیب جوشکاری متقارن می‌توان این اعوجاج‌ها را کاهش داد. 2 Increasingly, Welding is used in industry for assembled various products, such as ships, cars, trains and bridges. Welding distortion often results such as lack of accuracy during assembly and will have increases manufacturing costs. So, predict and reduce welding distortion is very important to improve the quality of welded structures.  In this study, firstly, a prediction method of welding distortion, which merges thermo-elastic-plastic finite element method (FEM) and large deformation elastic FEM based on inherent strain theory, was developed. Secondly, the inherent deformations of weld joints in a large thin plate panel structure were calculated using the thermo-elastic-plastic FEM and their specifications were also examined. Then, using the obtained inherent deformations, the usefulness of the proposed elastic FEM was demonstrated through the prediction of welding distortion in the large thin plate panel structures. Finally, the influences of welding sequence on distortion were investigated. The results of elastic analysis shows distortion in edges and interior parts of the panels, that can be reduced by changing welding sequence to symmetrical welding sequence. 13 25 2017/06/82020/01/28 1398/11/8 2018/12/62020/01/28 1398/11/8 سعید شادکام S. Shadkam دانشکده مهندسی دریا، دانشگاه صنعتی امیرکبیر، تهران ایران اسلام رنجبرنوده E. Ranjbar Nodeh دانشکده مهندسی معدن و متالورژی، دانشگاه صنعتی امیرکبیر، تهران ایران مهدی ایرانمنش M. Iranmanesh مهندسی دریا، دانشگاه صنعتی امیرکبیر، تهران ایران Welding simulation Elastic method Reinforced panel Welding sequence Distortion شبیه سازی جوش روش الاستیک پانل تقویت شده ترتیب جوشکاری اعوجاج. [1] Watanabe, Masaki, and Kunihiko Satoh. "Fundamental study on buckling of thin steel plate due to bead-welding." Journal of the Japan Welding Society27.6 (1958): 313-320.##[2] Nomoto, Toshiharu, Shoji Takechi, and Kazuhiro Aoyama. "Basic Studies on Accuracy Management System Based on Estimating of Weld Deformations." Journal of the Society of Naval Architects of Japan 1997.181 (1997): 249-260.## [3] Ueda, Yukio, and Taketo Yamakawa. "Analysis of thermal elastic-plastic stress and strain during welding by finite element method." Transactions of the Japan Welding Society 2.2 (1971): 90-100.##[4]Wang, Jiangchao, Ninshu Ma, and Hidekazu Murakawa. "An efficient FE computation for predicting welding induced buckling in production of ship panel structure." Marine Structures 41 (2015): 20-52.##[5]Deng, Dean, Hidekazu Murakawa, and Wei Liang. "Numerical simulation of welding distortion in large structures." Computer methods in applied mechanics and engineering 196.45 (2007): 4613-4627.##[6]Liang, W., et al. "Prediction of welding distortion by elastic finite element analysis using inherent deformation estimated through inverse analysis." Welding in the World 49.11-12 (2005): 30-39.##[7] Wang, Jiangchao, et al. "Investigation of buckling deformation of thin plate welded structures." The Twenty-first International Offshore and Polar Engineering Conference. International Society of Offshore and Polar Engineers, 2011.##[8] Wang, Jiangchao, et al. "Numerical prediction and mitigation of out-of-plane welding distortion in ship panel structure by elastic FE analysis." Marine Structures 34 (2013): 135-155.##[9] Murakawa, Hidekazu. "Computational welding mechanics and concept of inherent strain for industrial applications." Materials science forum. Vol. 539. Trans Tech Publications, 2007.##[10]Wang, Jiangchao, et al. "Welding distortion prediction with elastic FE analysis and mitigation practice in fabrication of cantilever beam component of jack-up drilling rig." Ocean Engineering 130 (2017): 25-39.##[11]UEDA, Yukio, et al. "Establishment of Computational Welding Mechanics (Mechanics, Strength & Structural Design)." (1995).##[12]Deng, Dean, and Hidekazu Murakawa. "FEM prediction of buckling distortion induced by welding in thin plate panel structures." Computational Materials Science 43.4 (2008): 591-607.##[13] Murakawa, Hidekazu, Dean Deng, and Ninshu Ma. "Concept of inherent strain, inherent stress, inherent deformation and inherent force for prediction of welding distortion and residual stress." (2010).##[14]Wang, Jiangchao, et al. "Investigation of buckling deformation of thin plate welded structures." The Twenty-first International Offshore and Polar Engineering Conference. International Society of Offshore and Polar Engineers, 2011.## ##

ارزیابی سرعت پیشروی ابزار بر رفتار آلیاژ Al-7075 در حین جوشکاری اصطکاکی اغتشاشی با استفاده از روش اجزاء محدود The evaluation of the tool's velocity on the behavior of the Al-7075 alloy during friction stir welding using finite element method 1 1 در این پژوهش تأثیر سرعت پیشروی ابزار بر رفتار مکانیکی آلیاژ Al-7075 در حین عملیات جوشکاری اصطکاکی اغتشاشی شبیه­سازی شد. در این شبیه­سازی از روش لاگرانژی با ماده صلب- ویسکو پلاستیک استفاده شد. نتایج حاصل از دمای فرایند بدست آمده از روش شبیه­سازی با انجام آزمون تجربی جوشکاری صحت سنجی شد و با استفاده از روابط مشخصه تنش، کرنش و دما در آلیاژ Al-7075 تغییرات و رابطه بین استحکام ماده و سرعت پیشروی در حین فرایند جوشکاری توسط شبیه­سازی مورد مطالعه قرار گرفت. با استفاده از شبیه­سازی بوجود آمدن عیوب در حین جوشکاری نیز بررسی شد و توسط آزمون­های تجربی مورد صحت سنجی واقع شد. 2 In this study, the effect of tool's advance velocity on the mechanical behavior of the Al-7075 alloy during friction stir welding was simulated. In this simulation, the Lagrangian method with rigid-Visco-plastic material was used. The results of the process temperature obtained by the simulation method were verified by the experimental welding test. Using the characteristic stress, strain and temperature relationships in the Al-7075 alloy, the changes and the relationship between the material strength during the welding process by simulation was studied. The generated simulation defects was verified by experimental test. 27 37 2017/06/82020/01/282018/03/9 1396/12/18 2018/12/62020/01/282019/04/7 1398/1/18 نیما مارچین N. Marchin دانشکده مهندسی مواد، دانشگاه صنعتی مالک اشتر، اصفهان ایران nima.marchin@gmail.com عبدالرضا سلطانی پور A.R. Soltanipoor مجتمع مکانیک، دانشگاه صنعتی مالک اشتر، اصفهان ایران a.r.soltanipoor@gmail.com خسرو فرمنش K. Farmanesh مجتمع هوا دریا- دانشگاه صنعتی مالک اشتر- فارس ایران kfarmanesh@gmail.com Friction Stir Welding finite element strength aluminum alloy 7075 Al-7075 فرایند جوشکاری اصطکاکی اغتشاشی شبیه‌سازی استحکام اتصال جوش سالم ##[1] P. Ulysse, Three-dimensional "modeling of the friction stir welding process", International Journal of Machine Tool and Manufacture, 2002, A42, pp.1549-1557.##[2] G. Buffa, J. Hua, R. Shivpuri and L. Fratini, "A continuum based FEM model for friction stir welding model development”, Mater. Sci. Eng. 2006, A419, pp.389–396.##[3] H. W. Zhang, Z. Zhang and J. T. Chen, "3D modeling of material flow in friction stir welding under different process parameters", Journal of Materials Processing Technology, 2007, A183, pp. 62-70.##[4] Z. Feng, X. L. Wang, S. A. David and P. S. Skald, "Modelling of residual stresses and property distributions in friction stir welding of aluminum alloy 6061-T6", Science and Technology of Welding and Joining, 2007, pp. 348-356.##[5] Z. Zhang and H. W. Zhang, "Numerical studies on controlling of process parameters in friction stir welding", Journal of Materials Processing Technology, 2009, A209, pp. 241-270.##[6] L. Fratini, G. Macalusoa and S. Pasta, "Residual stresses and FCP prediction in FSW through a continuous FE model", Journal of Materials Processing Technology, 2009, A209, pp. 5465–5474.##]7[ توحید عظیم‌زادگان/ سیامک سراج‌زاده، "بررسی عددی اثر سرعت‌های حرکت طولی و چرخشی بر جوشکاری اصطکاکی اغتشاشی در آلیاژ آلومینیم T6-7075"، شکل‌دهی فلزات و مواد، 1387، 87.##[8] S. D. Ji, Y. Y. Jin, Y. M. Yue, S. S. Gao, Y. X.Huang and L. Wang, "Effect of Temperature on Material Transfer Behavior at Different Stages of Friction Stir Welded 7075-T6 Aluminum Alloy", J. Mater. Sci. Technology, 2013, pp. 955-960.##[9] M. Abbasi, B. Bagheri and R. Keivani, "Thermal analysis of friction stir welding process and investigation into affective Parameters using simulation", Journal of Mechanical Science and Technology, 2015, pp. 861-866.##[10] S.Kbayashi, Soo-IK.Oh, T.Altan, "Metal forming and the finite element method", 1989, Oxford University Press, New York.##[11] Y. V. R. K. Prasad and S. Sasidhara, "Hot working guide, first edition", 1997, ASM International. ##

مطالعه ریزساختار و ریزسختی جوش فولاد زنگ نزن 316L جوشکاری شده به روش TIG, A-TIG, FB-TIG Study of Microstracture and Microhardness of Welded Austenic Stainless Steel 316L by TIG, A-TIG and FB-TIG Methods. 1 1 در این تحقیق تغییرات عمق­ نفوذ و ریزساختار و ریزسختی جوش فولاد زنگ­نزن L316 در سه حالت TIG، A-TIG و FB-TIG مطالعه و با یکدیگر مقایسه گردید. پس از انتخاب فلاکس بهینه تأثیر آن بر عمق نفوذ، ریزساختار و میکروسختی جوش فولاد زنگ­نزن L316 جوشکاری شده به روش­های A-TIG و FB-TIG بررسی و با نمونه TIG مقایسه گردید. مشاهده شد عمق نفوذ و نسبت عمق به عرض در روش FB-TIG نسبت به دو روش دیگر اندکی بیش­تر است. همچنین در روش A-TIG در خط مرکزی جوش وسعت دندریت­های هم­محور مرکزی نسبت به روش FB-TIG کاهش یافته­ است. بررسی میکروسختی این سه نمونه نشان داد که سختی خط مرکزی جوش در A-TIG و FB-TIG بیش­تر ازTIG است. 2 In this study the effect of activating fluxes on the penetration depth, microstructure and microhardness of AISI316L austenitic stainless steel were evaluated by three TIG process variations (TIG, A-TIG and FB-TIG) and the results were compared together.. After selecting the optimal flux in the second stage, the effect of that on the penetration depth, microstructure and weld microhardness of  welded 316L austenitic stainless steel by A–TIG and FB-TIG methods, were evaluated and  the results were compared by the sample which was welded by TIG process. At this stage, it was found that the depth and width to depth ratio in FB-TIG method is slightly greater than the other two methods. Also in FB-TIG method, eqiaxed dendritic zone in the center line of weld is slightly greater than in A-TIG method. Study of microhardness of weld in three methods shows that in A-TIG and FB-TIG methods hardness of center line is more than TIG method. 39 50 2017/06/82020/01/282018/03/92018/06/21 1397/3/31 2018/12/62020/01/282019/04/72018/11/18 1397/8/27 نگار رحیمی N. Rahimi دانشکده مهندسی مواد - دانشگاه صنعتی سهند ایران توحید سعید T. Saed دانشکده مهندسی مواد - دانشگاه صنعتی سهند ایران saeid@sut.ac.ir 316L austenitic stainless steel A-TIG FB-TIG penetration depth microstructure microhardness فولاد زنگ نزن 316 A-TIG FB-TIG عمق نفوذ ریزساختار میکروسختی ##1. 1. D. J. Renzo, Corrosion Resistant Materials Handbook, 4th edition, United States of America Noyes Data Corporation, 1985.##2. . ج. لیپولد، م. کوتکی، متالورژی جوشکاری و جوش‌پذیری فولادهای زنگ نزن، ترجمه مرتضی شمعانیان، محمد رحمتی، انتشارات جهاد دانشگاهی صنعتی اصفهان، بهار 87.##3. N. Moslemi, N. Redzuan, N. Ahmad, T. N. Hor, Effect of Current on Characteristic for 316 Stainless Steel Welded Joint Including Microstructure and Mechanical Properties, 12th Global Conference on Sustainable Manufacturing, 2015.##4. N. B. Ramlee, Effect of PH, Temperature and Chloride Concentrations on the Corrosion Behavior of Welded 316L Stainless Steel, M.S.C Thesis, faculty of mechanical engineering university technology malaysia, 2008.##5. K. H. Tseng, Development and Application of Oxide-Based Flux Powder for Tungsten Inert gas Welding of Austenitic Stainless Steel, Institute of Materials Engineering, National Pingtung University of Science and Technology, Powder Technology, Vol. 233, 2013.##6. Y. Huang, D. Fan, and Q. Fan, Study of Mechanism of Activating Flux Increasing Weld Penetration of AC A-TIG Welding for Aluminum Alloy, Frontiers of Mechanical Engineering in China, vol. 2, 2007.##7. S. Sire and S. Marya, On the Development of a New Flux Bounded TIG Process (FB-TIG) to Enhance Weld Penetrations in Aluminium 5086, International Journal of forming process, vol. 5, 2002.##8. R. W. Messler, Principles of Welding, Materials Science and Engineering Department Rensselear Polytechnic Institute:, Wiley-Interscience Publication, 1999.##9. S. Kou, Welding Metallurgy, Department of Materials Science and Engineering University of Wisconsin, Wiley, 2003.##10. ع. فرزادی، شبیه سازی انتقال حرارت، سیلان سیال و ریزساختار انجمادی حوضچه جوش در جوشکاری تیگ، پایان‌نامه دکتری دانشگاه صنعتی شریف، گرایش جوشکاری.1387.##11. P. Paillard, A. Berthier, M. Carin, S. Pellerin, and F. Valensi, Physical and chemical mechanisms occurring during A-TIG Welding: Comparison between experimental investigation and simulation, Materials Science Forum, 2010.##12. L. Liu, Z. Zhange, G. Song, and Y. Shen, Effect of Cadmium Chloride Flux in Active Flux TIG Welding of Magnesium Alloys, Materials Transactions, Vol. 47, 2006.##13. . Q. M. Li, X. h. Wang, Z. D. Zou, and J. Wu, Effect of Activating Flux on Arc Shape and Arc Voltage in Tungsten Inert Gas Welding,” Transaction of Nonferrous Metals Society of chaina, vol. 17, 2007.##14. S. Shyu, H. Huang, K. Tseng, and C. Chou, Study of the Performance of Stainless steel A-TIG Welds, journal of Materials Engineerring of Performance, vol. 17, 2008.##15. K. H. Tseng and C.Y . Hsu, Performance of Activated TIG Process in Austetenitic Stainless steel welds, Journal of Materials Processing Technology, vol. 211, 2011.##16. T. S. Chern, K. H. Tseng and H. L. Tsai, Study of the Characteristics of Duplex Stainless steel Activated Tungsten Inert Gas Welds, Material & Design, vol. 211, 2011.##17. H. Y. F. Sandor, Dobranszky, and G. Kaptay, An Improved Theoretical Model for A-TIG Welding Based on Surface Phase Transition and Reversed Marangoni Flow, The Minerals, Metals & Materials Society and ASM International, vol. 44, 2013.##18. J. Lowke, M. Tanaka and M. Ushio, Mechanisms Giving Increased Weld Depth due to a Flux, Journal of Physics, D: Applied Physics, vol. 38, 2005. ##

تحولات ریزساختاری فولاد زنگ‌نزن آستنیتی 304 در فرایند جوشکاری همزن اصطکاکی Microstructural evolution of 304 austenitic stainless steel in friction stir welding process 1 1 جوش بدون درزی بر روی ورق 2 میلیمتری فولاد زنگ­نزن آستنیتی 304 با روش جوشکاری همزن اصطکاکی با سرعت چرخشی 400 دور بر دقیقه و سرعت پیشروی 50 میلیمتر بر دقیقه ایجاد گردید. مشاهدات ریزساختاری توسط میکروسکوپ نوری نشان داد که اصلاح ریزساختاری شدیدی در ناحیه جوش صورت گرفته است. همچنین، نتایج حاصل از آزمون پراش الکترون‌های برگشتی (EBSD) نشان داد که کسر بزرگی از مرزدانه ­های کوچک زاویه با وقوع بازیابی دینامیکی در ناحیه متاثر از عملیات ترمومکانیکی و کسر بزرگی از مرزدانه­های بزرگ زاویه با وقوع تبلور مجدد دینامیکی در ناحیه همزده توسعه یافته‌اند. تصویر قطبی صفحات 100 نشان داد که اجزای بافت برشی  A*1 و  A*2 در ناحیه همزده بوجود آمده است.   2 Friction stir welding (FSW) was conducted on AISI 304 austenitic stainless steel plate with 2 mm thickness. The FSW was performed at a welding and rotational speeds of 50 mm/min and 400 rpm, respectively. Microstructure observations by the optical microscopy showed that a severe grain refinement occurred in the stir zone (SZ). Electron backscattered diffraction analysis (EBSD) results indicated that high fraction of low angle grain boundaries (LAGBs) developed in the thermo-mechanically affected zone (TMAZ) through the occurrence of the dynamic recovery. Moreover, in the path from the TMAZ towards the SZ, the fraction of high angle grain boundaries (HAGBs) increased with decreasing the fraction of LAGBs through the occurrence of continuous dynamic recrystallization (CDRX). 100 Pole figure showed the formation of shear texture components of A*1 and A*2 in the SZ which implied the occurrence of CDRX mechanism.   51 59 2017/06/82020/01/282018/03/92018/06/212018/07/9 1397/4/18 2018/12/62020/01/282019/04/72018/11/182018/09/12 1397/6/21 سجاد امامی S. Emami دانشگاه صنعتی سهند تبریز ایران sajjademami@yahoo.com توحید سعید T. Saeid دانشگاه صنعتی سهند تبریز ایران saeid@sut.ac.ir Friction stir welding Stainless steels Dynamic recovery Dynamic recrystallization Shear texture. جوشکاری همزن اصطکاکی فولادهای زنگ نزن بازیابی دینامیکی تبلور مجدد دینامیکی بافت برشی. ##[1] Park, S.H.C., Sato, Y.S., Kokawa, H., Okamoto, K., Hirano, S., and Inagaki, M., Microstructural characterisation of stir zone containing residual ferrite in friction stir welded 304 austenitic stainless steel, Science and Technology of Welding and Joining, 10 (2005) 550-556.##[2] Sato, Y.S., Nelson, T.W., Sterling, C.J., Recrystallization in type 304L stainless steel during friction stirring, Acta Materialia, 53 (2005) 637–645.##[3] Marchattiwar, A., Sarkar, A., Chakravartty, J.K., and Kashyap, B.P., Dynamic recrystallization during hot deformation of 304 austenitic stainless steel, Journal of Materials Engineering and Performance, 22 (2013) 2168–2175.##[4] Kou S, Welding Metallurgy, 2nd edition, John Wiley & Sons Publication, 2003.##[5] Tokita, S., Yokoyama, T., Kokawa, H., Sato, Y.S, Fujii, H.T, Friction stir welding of grain boundary engineered 304 austenitic stainless steel, Proceeding of National Meeting of JWS, 2013, 407-408. ##[6] Mishra, R.S., Ma, Z.Y., Friction stir welding and processing, Materials Science and Engineering R 50 (2005) 1–78.##[7] Humphreys, F.J., Hatherly, M., Recrystallization and related annealing phenomena, 2nd edition, Elsevier, 2004.##[8] Meran, C., Kovan, V., Alptekin, A., Friction stir welding of AISI 304 austenitic stainless steel, Mat.-wiss. u. Werkstofftech, 10 (2007), 829-835.##[9] Reynolds, A.P., Tang, W., Gnaupel-Herold, T., Prask, H., Structure, properties, and residual stress of 304L stainless steel friction stir welds, Scripta Materialia 48 (2003) 1289–1294.##[10] Park, S.H.C., Sato, Y.S., Kokawa, H., Okamoto, K., Hirano, S., Inagaki, M., Rapid formation of the sigma phase in 304 stainless steel during friction stir welding, Scripta Materialia 49 (2003) 1175–1180.##[11] Meran, C., Canyurt, O.E., Friction Stir Welding of austenitic stainless steels, Journal of Achievements in Materials and Manufacturing Engineering, 43/1 (2010) 432-439.##[12] Mironov, S., Sato, Y.S., Kokawa, H., Microstructural evolution during friction stir-processing of pure iron, Acta Materialia 56 (2008) 2602–2614.##[13] Saeid, T., Abdollah-zadeh, A., Shibayanagi, T., Ikeuchi, K., Assadi, H., On the formation of grain structure during friction stir welding of duplex stainless steel, Materials Science and Engineering A 527 (2010) 6484–6488.##[14] Rezaei-Nejad, S.S, Abdollah-zadeh, A., Hajian, M., Kargar, F., Seraj, R., Formation of Nanostructure in AISI 316L Austenitic Stainless Steel by Friction Stir Processing, Procedia Materials Science 11 (2015) 397 – 402.##[15] Liu, F.C., Nelson, T.W., In-situ grain structure and texture evolution during friction stir welding of austenite stainless steel, Materials & Design 115 (2017) 467–478.##[16] Cho, H.H., Han, H.N., Hong, S.T., Park, J.H., Kwon, Y.J., Kim, S.H., Steel, R.J., Microstructural analysis of friction stir welded ferritic stainless steel, Materials Science and Engineering A 528 (2011) 2889–2894.##[17] Beladi, H., Cizek, P., and Hodgson, P.D., Dynamic recrystallization of austenite in Ni-30 Fe model alloy: microstructure and texture evolution, Metallurgical And Materials Transactions A, 40A (2009) 1175-1189.##[18] Mirzadeh, H., Cabrera, J.M., Najafizadeh, A., Calvillo, P.R., EBSD study of a hot deformed austenitic stainless steel, Materials Science and Engineering A 538 (2012) 236–245.##[19] Badiola, D.J., Iza-Mendia, A., Guti´errez, I., Study by EBSD of the development of the substructure in a hot deformed 304 stainless steel, Materials Science and Engineering A 394 (2005) 445–454.##[20] Mironov, S., Sato, Y.S., Kokawa, H., Microstructural evolution during friction stir-processing of pure iron, Acta Materialia 56 (2008) 2602–2614.##[21] Suwas, S., Ray, R.K., Crystallographic texture of materials, Springer, 2014.##[22] Santos, T.F.A., Torres, E.A., Lippold, J.C., and Ramirez, A.J., Detailed microstructural characterization and restoration mechanisms of duplex and superduplex stainless steel friction-stir-welded joints, Journal of Materials Engineering and Performance, 2016, DOI: 10.1007/s11665-016-2357-0.##[23] Dehghan-Manshadi, A., Beladi, H., Barnett, M.R. and Hodgson, P.D., Recrystallization in 304 austenitic stainless steel, Materials Science Forum, 467-470 (2004) 1163-1168. ##

تحلیل دما و تنش در اتصال لوله ای جوش صلیبی با استفاده از نرم افزارSimufact Welding Stress and temperature analysis in tubular x-joints using simufact welding 1 1 اتصالات لوله‌ای جوشکاری شده به دلیل کارایی بالا در مقابل فشار، خمش و پیچش ﺑﻪﻃﻮرﮔﺴﺘﺮده ای در اﺗﺼﺎﻻت ﺳﺎزهﻫﺎی ﻣﺘﻨﻮﻋﯽ در صنعت مورد استفاده قرار می‌گیرند.ﺳﺎزهﻫﺎی ﺟﻮﺷﮑﺎری ﺷﺪه جزو ﻗﺴﻤﺖﻫﺎی اصلی ﮐﺸﺘﯽﻫا، ﺳﺎﺧﺘﻤﺎنﻫﺎ، ﭘﻞﻫﺎ، ﻟﻮﻟﻪﻫﺎی اﻧﺘﻘﺎلﮔﺎز، ﻣﺠﺮاﻫﺎی ﻓﺸﺎر و ﺗﺠﻬﯿﺰات اﻧﺘﻘﺎل ﻗﺪرت در صنایع کشتی سازی، ساختمان سازی، نفت، گاز، پتروشیمی و نیروگاه‌ها ﻣﯽباشند. نمونه ای از اتصالات جوشی لوله ای، اتصال صلیبی می باشد که در این پژوهش مورد بررسی قرار گرفته است.ﻫـﺪف اصلیﮐـﺎرﺣﺎﺿـﺮﺑﺮرﺳﯽتوزیع حرارت وﺗﻨﺶ ﻫﺎیﭘﺴـﻤﺎﻧﺪﻧﺎﺷـﯽ از فرآیند ﺟـﻮشکـﺎری سه مرحله ای دریک اتصال صلیبی از جنسSt52 با استفاده از نرم افزار تخصصی Simufact Welding می باشد. ﻓﺮآیﻨﺪﺟﻮﺷﮑﺎریﺷﺎﻣﻞسه ﻣﺮﺣﻠﻪ ﺟﻮﺷﮑﺎری با اﻟﮑﺘﺮود دﺳﺘﯽ است. ﻣﺪل اﺟﺰاء ﻣﺤﺪود ﺷﺎﻣﻞ ﺧﻮاص ﺣﺮارﺗﯽ و ﻣﮑﺎﻧﯿﮑﯽ ﻓﻠﺰ ﭘﺎیﻪ و ﻓﻠﺰﺟﻮش ﺑﻪ ﺻﻮرتﺗﺎﺑﻌﯽ از دﻣﺎ اﺳﺖ. ﻫﻤﭽﻨﯿﻦاز اﺑﺰارﻫﺎیﭘﯿﺸﺮﻓﺘﻪ ﻣﺪلﺳﺎزی ﻣﺎﻧﻨﺪ انطباق شبکه در طول فرایند و شبکه بندی سازگار با محل جوشکاری، ﺗﻮﻟﺪ و مرگ اﻟﻤﺎن وﺣﺮﮐﺖ ﻣﻨﺒﻊﺣﺮارﺗﯽاﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. شبیه سازی نشان داد که ﺗﻨﺶﻫﺎی ﭘﺴﻤﺎﻧﺪ ﻗﺎﺑﻞﺗﻮﺟﻬﯽ در اﺗﺼﺎل ﺑﻌﺪ از ﺟﻮشﮐﺎری ایﺠﺎد می شود. ﻣﻘﺎیﺴﻪﻧﺘﺎیﺞ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﻧﺘﺎیﺞﻋﺪدی و اﻧﺪازهﮔﯿﺮیﻫﺎی ﺗﺠﺮﺑﯽ ﺗﻄﺎﺑﻖ ﺧﻮﺑﯽ ﺑﺎ یﮑﺪیﮕﺮ دارد و ﻣﺪل موجود ﻣﯽﺗﻮاﻧﺪ ﭘﯿﺶﺑﯿﻨﯽﺧﻮﺑﯽ از ﺗﻮزیﻊ دﻣﺎ و ﺗﻨﺶﭘﺴﻤﺎﻧﺪ در ایﻦﻓﺮآیﻨﺪﺟﻮﺷﮑﺎری داﺷﺘﻪ ﺑﺎﺷﺪ. 2 Welded tubular joints are widely used in various industry structures for high efficiency subjected to pressure, bending and twisting.Welded structures are the main parts of structures, buildings, bridges, gas pipes, pressure vessels and power transmission equipment in the ship building, construction, oil, gas, petrochemical industries and power plants.A sample of pipe-welded joints is a X-tubular joint that has been investigated in this study.The main objective of the present work is to investigate the heat transfer and residual stress caused by the three-stage welding process in X-tubular joint made of St52 using Simufact Welding software.The welding process involves three welding steps using arc welding. The finite element model contains the thermal and mechanical properties of base metal and welding metal as a function of temperature.Also, advanced modeling tools such as mesh adaptation during the process and meshing compatible with the welding site, the birth and death technique of the element and the source of heat transfer have been used.Welding simulation showed that significant residual stresses were created in the joint after welding. Comparison of the results shows that the numerical results and empirical measurements are in good agreement with each other and the existing model can provide a good prediction of temperature distribution and stress control in this welding process. 61 75 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/28 1398/11/8 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/28 1398/11/8 نبرد حبیبی N. Habibi گروه مهندسی مکانیک، دانشکده مهندسی دانشگاه کردستان، سنندج ایران حسن اسکندری H. Eskandari گروه مهندسی مکانیک، دانشکده مهندسی دانشگاه کردستان، سنندج ایران Welding simulation Adaptive and compatible mash Simufact welding Temperature distribution Residual stress. شبیه سازی جوش منبع حرارتی شبکه بندی انطباقی و سازگار Simufact Welding توزیع دما ﺗﻨﺶﭘﺴﻤﺎﻧﺪ. ##[1] Islam, M., and Buijk, A., Rais-Rohani, M., and Motoyama,k., “Simulation-based numerical optimization of arc welding process for reduced distortion in welded structures”,Finite Elements in Analysis and Design, Vol.84, pp. 54–64, 2014.##[2] Mandal, N.R., “Welding and distortion control”, UK: Alpha ScienceInternational Ltd, 2004.##[3] Ayjwat,A.,and Bhatti, Zuheir.Barsoum.,and Hidekazu,Murakawa.,and Imad,Barsoum.,“Influence of thermo-mechanical material properties of different steel grades on welding residual stresses and angular distortion”,Materials and Design,Vol 65,pp. 878–889, 2015.##[4] Mackerle, J.,“Finite element analysis and simulation of welding: a bibliography (1976–1996)”,Model Simul Mater Sci Eng, Vol. 4,pp.501–33, 1996.##[5] Mackerle, J.,“Finite element analysis and simulation of welding – an addendum: a bibliography (1996–2001)”,Model Simul Mater Sci Eng, Vol. 10, pp. 295–318, 2002.##[6] Seyyedian-Choobi, M., and Haghpanahi, M., Sedighi, M.,“Effect of welding sequenceand direction on angular distortions in butt-welded plates”,J Strain Anal EngDes, Vol. 47 (1),pp. 46–54, 2011.##[7] Teng, T.L., and Chang, P.H., and Tseng. W.C.,“Effect of welding sequences on residual stresses”,Comput Struct, Vol. 81(5), pp. 273–86, 2003.##[8] Liang, W., and Murakawa, H.,“An inverse analysis method to estimate inherentdeformations in thin plate welded joints”, Mater Des, Vol. 40, 190–198, 2012.##[9] Bachorski, A., and Painter, M.J., and Smailes, A.J., and Wahab, M.A.,“Finite-element prediction ofdistortion during gas metal arc welding using the shrinkage volume approach”,J Mater Process Technol, Vol. 92-93, pp. 405–409, 1999.##[10] Bhatti, A.A., and Barsoum, Z.,“Development of efficient three-dimensional weldingsimulation approach for residual stress estimation in different welded joints”,JStrain Anal Eng Des,Vol. 47(8), pp. 539–552, 2012.##[11] Bhatti, A.A., and Barsoum, Z., and Khurshid, M.,“Development of a finite element simulationframework for the prediction of residual stresses in large welded structures”,Comput Struct, Vol. 133, 1–11, 2014.##[12] Barsoum, Z., Lundback, A.,“Simplified FE welding simulation of fillet welds-3D effects on the formation residual stresses”,Eng Fail Anal,Vol. 16(7), 2281–2289, 2009.##[13] Lindgren, L.E., and Haggblad H.A., and Mcdill. J.M.J., Oddy, A.S.,“Automatic remeshing for three-dimensional simulation of welding finite element”,Comput Methods Appl Mech Eng,Vol. 147, pp. 401–409, 1997.##[14] Heinze, C., and Schwenk, C., and Rethmeier, M.,“Influences of mesh density and transformation behavior on the result quality of numerical calculation of welding induced distortion”,Simul Model Pract Theory, Vol. 19(9), pp.1847–1859, 2011.##[15] William.Perret.and Christopher.Schwenk,and Michael. R. Ethmeier., and Thate, R. Raphael., and Uwe, Alber., “Case Study for Welding Simulation in the Automotive Industry”, Weldingin the World, Vol. 55 (11-12), pp. 89-98, 2011.##[16] William, Perret.“Welding Simulation of Complex Automotive Welded Assembly-Possibilities and Limits of the Application of Analytical Temperature Field Solutions”, ISBN3981594401 BAM, 184 pages, 2013.##[17] “Simufact welding”, http://www.simufact.de/ en/solutions/ sol_weld. Html, 2015.##[18] MSC. Simufact Welding V6, Simufact-Info Sheet-Heat Source Geometry& Simufact-Info Sheet-User SubroutineandInfo Sheet-Meshing.##[19] Dar, N.U., and Qureshi, E.M., and Hammouda, M.M.I.,“Analysis of weld induced residual stresses and distortions in thin walled cylinders”,J Mech Sci Technol, Vol. 55, pp. 1118–1131, 2009.##[20] Yu, C.L., and Chen. Z.P., and Wang, Ji.and Yan, ##Shun-juan., and Yang. Li-Cai., “Effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells”, J ZhejiangUniv-Sci A, Vol. 13 (3), ##pp. 79-90, 2011.##[21] Sagalevich, V.M., and Shvetsov, V.A., and Baumana, N.E.,“Distortion in welding circumferential seams in thin walled shells”,England: Welding production, The Welding Institute, 1970.##[22] Ohsawa, M., and Nakajma, H., and Nagai. 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اثر هندسه پین بر خواص مکانیکی کامپوزیت آلومینیم6061-آلومینا ایجاد شده به روش جوشکاری اصطکاکی اغتشاشی The Effect of pin geometry on the mechanical property of Aluminium 6061-alumina composite made by friction stir welding 1 1 امروزه علاوه بر ایجاد اتصال با روش جوشکاری اصطکاکی اغتشاشی، فرآیند کامپوزیت‌سازی نیز‌ همزمان نیز صورت می‌گیرد. هدف اصلی تحقیق حاضر بررسی اثر هندسه پین بر خواص نانوکامپوزیت آلومینیم6061-آلومینا ایجاد شده به روش جوشکاری اصطکاکی اغتشاشی است. بدین منظور انجام جوشکاری اصطکاکی اغتشاشی با انتخاب پنج نوع هندسه پین بر روی آلیاژ آلومینیوم6061 که ذرات Al2O3 در آن جاگذاری شده انجام گردید و نمونه‌ها با استفاده از آزمون‌های کشش، سختی سنجی، میکروسکوپ نوری و الکترونی مورد بررسی قرار گرفت. پین شش ضلعی منتظم به علت داشتن شش صفحه صاف و حرکت ضربه‌ای در حین چرخش، اغتشاش مناسبی را ایجاد کرده که باعث ایجاد بیشترین استحکام کششی و درصد ازدیاد طول به ترتیب به مقدار  MPa 198و 25/10 و کمترین اندازه دانه 3/13 میکرون شده است. در نمونه جوشکاری شده با پین استوانه‌ای رزوه‌دار به علت عدم ضربه در حین چرخش، سیلان نامناسب ذرات تقویت کننده و تجمع آن در محل اغتشاش، کمترین استحکام کششی و درصد ازدیاد طول به ترتیب به مقدارMPa  5/133و 95/1 درصد حاصل گردید.   2 Today in addition to Join by friction stir welding, the composite fabrication process is also performed simultaneously. The main purpose of the present research is to investigate the effect of pin geometry on the property of Aluminum 6061- alumina nanocomposite created by friction stir welding. For this purpose friction stir welding was carried out by selecting five types of pin geometries on Aluminum 6061 in which Al2O3 particles were deposited and the samples were examined by tensile and hardness tests, optical and electron microscope. Samples were investigated by tensile and hardness test, optical and electronic microscopy. Regular hexagonal pins due to having six smooth face and impulsive movement during rotation, caused a good perturbation which resulted in maximum tensile strength and elongation percentage of 198 MPa and 10.25 and minimum grain size of 13.3 micron, respectively. In the sample welded by a threaded cylindrical pin due to non-impact during rotation, inappropriate flow of reinforcing particles and its accumulation at perturbation the lowest tensile strength and elongation percentage of 133.5 MPa and 1.95%, respectively, were observed. 77 88 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/282020/02/9 1398/11/20 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/282020/02/9 1398/11/20 مجید بلباسی M. Belbasi گروه مهندسی نفت، معدن و مواد، دانشکده فنی و مهندسی، دانشگاه آزاد واحد تهران مرکزی، تهران، ایران ایران dr.belbasi@gmail.com مهرداد رضایی M. Rezae گروه مهندسی نفت، معدن و مواد، دانشکده فنی و مهندسی، دانشگاه آزاد واحد تهران مرکزی، تهران، ایران ایران Friction stir welding Pin geometry Aluminum 6061 Al2O3 particles. جوشکاری اصطکاکی اغتشاشی هندسه پین آلومینیوم 6061 ذرات Al2O3. ##[1] Mishra, R., Ma, ZY. and Charit, I., “Friction stir processing: a novel technique for fabrication of surface composite”, Materials Science Engineering A, Vol. 341(1–2), pp. 307–310, 2003.##[2] Surekha, K., Els-Botes, A., “Development of high strength, high conductivity copper by friction stir processing” Materials & Design, Vol. 32(2), pp. 911–916, 2011.##[3] Azizieh, M., Kokabi, AH. and Abachi, P., “Effect of rotational speed and probe profile on microstructure and hardness of AZ31/Al2O3 nanocomposites fabricated by friction stir processing”, Materials & Design, Vol. 32(4), pp.2034–2041, 2011.##[4] Ma, ZY., Liu, FC. and Mishra, RS., “Superplastic deformation mechanism of an ultrafinegrained aluminum alloy produced by friction stir processing “, Acta Materials, Vol. 58(14), pp. 4693–4704, 2010.##[5] Peiqi, Li., Guoqiang, Y., Hengyu, W., Wei, G. and Xin, T., “Friction stir welding between the high-pressure die casting of AZ91magnesium alloy and A383 aluminum alloy”, Journal of Materials Processing Technology, Vol. 264, pp. 55-63, 2019.##[6] Kumar, A., Biswas, P., “The study of materialflow behaviour in dissimilar material FSW of AA6061and Cu-B370 alloys plates”, Journal of Manufacturing Processes, Vol. 34, pp. 96-105, 2018.##[7] Bahrami, M., Dehghani, K. and Besharati Givi, M. K., “A novel approach to develop aluminum matrix nano-composite employing friction stir welding technique”, Materials and Design, Vol. 53, pp. 217-225, 2014.##[8] Muthu Krishnan, M., Maniraj, J., Deepak, R. and Anganan, K., “Prediction of optimum welding parameters for FSW of aluminium alloys AA6063 and A319 using RSM and ANN”, Materials Today, Vol. 5 pp. 716–723, 2018.##[9] Venkateswara, R., Senthil Kumar, R.M., “Experimental Investigation On Effect Of Welding Parameters On The Friction Stir Welding Of AA 6061”, Materials Today, Vol. 5, pp. 12265–12272, 2018.##[10] Ashish, B., Saini, J. S. and Sharma, B., “A review of tool wear prediction during friction stir welding of aluminium matrix composite”, Transaction. Nonferrous Metals. Society. China, Vol. 26, pp. 2003−2018, 2016.##11. Marzoli, L.M.,Strombeck, A.V., Dos Santos, J.F., Gambaro, C. and Volpone, L.M, “Friction stir welding of an AA6061/Al2O3/20p reinforced alloy”, Composites Science and Technology, Vol. 66, pp. 363-371, 2006.##[12] Sharifitabar, M., Sarani, A., Khorshahian, S. and Shafiee Afarani, M., “Fabrication of 5052Al/Al2O3 nanoceramic particle reinforced composite via friction stir processing route, Materials & Design, Vol. 32(8–9), PP 4164-4172, 2011.##[13] Farahmand Nikoo, M., Parvin, N., Bahrami, M., “Al2O3-fortifed AA6061-T6 joint produced via friction stir welding: The effects of traveling speed on microstructure, mechanical, and wear properties”, Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, Vol. 231(6), pp. 534-543 , 2015. ##[14] Nascimento, F., Santos, T., Vilaça, P., Miranda, RM. and Quintino, L., “Microstructural modification and ductility enhancement of surfaces modified by FSP in aluminium alloys” Materials Science Engineering A, Vol. 506(1–2), pp. 16-24, 2009.##[15] Gopalakrishnan, S., Murugan, N., “Prediction of ##tensile strength of friction stir welded aluminium ##matrix TiC p particulate reinforced composite”## Materials & Design, Vol. 32(1), pp. 462-467, ##2011.##[16] Zahmatkesh, B., Enayati, MH., and Karimzadeh, F., “Tribological and microstructural evaluation of friction stir processed Al2024 alloy”, Materials & Design, Vol. 31(10), pp.4891–4896, 2010.##[17] Barmouz, M., Besharati Givi, MK., Seyfi, J., “On the role of processing parameters in producing Cu/SiC metal matrix composites via friction stir processing: Investigating microstructure, microhardness, wear and tensile behavior” Materials characterization, Vol. 62, pp. 108–117, 2011. ##

بررسی خواص مکانیکی و ریز ساختاری آلیاژ AZ31 جوشکاری شده به روش TIG و TIG پالسی Evolution of microstructures and mechanical properties of AZ31 magnesium alloy weldment with TIG and Pulsed TIG process 1 1 آلیاژهای منیزیم به دلیل داشتن خواصی مانند استحکام ویژه مناسب، وزن کم و خواص مکانیکی مطلوب کاربردهای زیادی را به خود اختصاص داده­اند. آلیاژ AZ31 از نظر جوش پذیری نسبت به سایر آلیاژهای منیزیم وضعیت مناسب­تری دارد بنابراین کاربرد بیشتری نسبت به سایر آلیاژهای منیزیم دارد. در این بررسی از روش جوشکاری TIG و TIG پالسی به منظور جوشکاری و اتصال آلیاژ AZ31 استفاده شد و در نهایت ریزساختار و خواص مکانیکی نمونه ها توسط میکروسکوپ نوری، میکروسکوپ الکترونی روبشی(SEM)، آزمون کشش و میکروسختی سنجی مورد بررسی قرار گرفتند. نتایج نشان داد که در ناحیه جوش رسوبات  β-Mg17Al12 تشکیل شده است و گرمای ورودی اندازه دانه­ها را تحت تاثیر قرار داده و منجر به تغییر در خواص مکانیکی شده است. نمونه جوشکاری به روش TIG با جریان A50 و فرکانس Hz60 بیشترین استحکام(MPa226) را در میان نمونه­های جوشکاری شده به روش TIG و TIG پالسی دارد. در میان نمونه­های جوشکاری شده به روش TIG پالسی نمونه جریان پیک A75 و جریان زمینه A35 بیشترین استحکام(MPa109) را دارد. 2 Magnesium alloys are very attractive materials owing to their properties of low density, high specific strength and stiffness, good castability, and weldability. AZ31 magnesium alloys in terms of weldability has better situation than the other, so it has more applications than other magnesium alloys. In this study, TIG and pulsed TIG welding method was used to welding the AZ31 alloy and finally microstructure and mechanical properties of welds with metallography, scanning electron microscopy (SEM), tensile test were examined. The results showed that the heat input affected the size of grains that are leading to changes in mechanical properties. Sample was welded with TIG welding with minimum current has maximum strength among the samples both pulsed TIG welding and TIG method. It is observed that with increasing frequency in TIG welding, strength is reduced. Despite the same IP and IB, higher frequency has created a stronger welding. Also increases the frequency leads to more fine-grained samples, resulting in increased strength. 89 102 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/282020/02/92018/10/10 1397/7/18 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/282020/02/92018/11/18 1397/8/27 سیده زهرا انوری Seyedeh Zahra Anvari دانشگاه پیام نور ایران szaanvari@gmail.com محمد رضا الهی Mohammad Reza Elahi دانش پژوهان ایران m.elahi69@yahoo.com AZ31 magnesium alloy TIG Mechanical properties آلیاژ منیزیم AZ31 جوشکاری قوس تنگستن تحت پوشش گاز محافظ (TIG) خواص مکانیکی. [1] Kulekci. M. K ,. London D.T., “Magnesium and its alloys applications in automotive industry” ,The International Journal of Advanced Manufacturing Technology, Vol. 39, pp 851-865, 2008.##[2] ASM Specialty Handbook, Magnesium and Magnesium Alloys,ASM Int. ,1999.##[3] Lei Z., Jiang Bi, Peng Li, Tao Guo, Yaobang Zhaob, Dengming Zhang, “Analysis on welding characteristics of ultrasonic assisted laser welding of AZ31B magnesium alloy’, Optics and Laser Technology 105 (2018) 15–22##[4] Shaoxing Z,Yang S.,China D.T ,” In Vitro Degradation, Hemolysis and MC3T3-E1 Cell Adhesion of Biodegradable Mg–Zn alloy”, Materials Science and Engineering C, Vol. 29, PP. 1907-1912, 2009.##[5] Yingwei S, Dayong S ., China D.T,” Biodegradable Behaviors of AZ31 Magnesium Alloy in Simulated Body Fluid”, Materials Science and Engineering C, Vol. 29, PP. 1039-1045, 2009.##[6] Wong H M ,Yeung K W.,China D.T,” A Biodegradable Polymer-Based Coating to Control the Performance of Magnesium Alloy Orthopaedic Implants”, Biomaterials, Vol. 31, PP. 2084-2096, 2010.##[7] Dingchuan X,Yeoheung Y,.USA D.T, “Corrosion Protection of Biodegradable Magnesium Implants Using Anodization”, Materials Science and Engineering C, Vol. 31, PP. 215- 223, 2011.## [8] Tuz. L, Kolodziejczak. P, Kolasa. A, "Structure of butt joint of as-cast magnesium alloy", Welding International, 30, pp. 43-47, 2014.##[9] Gou L., Tang A., Pan F., She J., Luo S., Ye J., Shi D., Rashad M. , “ Influence of Sn addition on mechanical properties of gas tungsten arc welded AM60 Mg alloy sheets”, Trans. Nonferrous Met. Soc. China, vol. 26, pp. 2051-2057, 2016.##[10] Asadi, P., Elhami, A., and Kazemi-Choobi K.Iran D.T. , Welding of magnesium alloys. INTECH Open Access Publisher, 2012.##[11] James.A .Toronto D.T ,”Localized corrosion of friction stir spot welds in mangnesium AZ31 alloy” , Materials Science and Engineering, pp.1-98, 2012.##[12] Yunhai.S, Zhengjun.L., China D.T., “Effect Of Magnetic Field on Microstructure and Properties of Magnesium Alloy Welded Joint with GTAW” ., Advanced Materials Research Vols. 189-193 pp 3507-3510, 2011.##[13] Chun M.L, Ching M.C.,China D.T.,“Evolution of microstructures and mechanical properties of AZ31B magnesium alloy weldment with active oxide fluxes and GTAW process”, Journal of the Chinese Institute of Engineers , Vol. 34, No. 8, pp, 1013–1023, 2011.##[14]Senthil Kumar T., Balasubramanian, V., and Sanavullah, M. Y., "Effect of pulsed current TIG welding parameters on tensile properties of AA6061 aluminium alloy", Indian Welding Society. PP. 29-39, (2005).## [15] Gokhale, A. A., Tzavaras, A. A., Brody, H. D., Ecer, G. M., Abbaschian, G. J., and David, S. A.,"Grain Refinement in Castings and Welds", TMS-AIME, Warrendale, PA, p. 223, (2005).##[16] Chen, J, Liu, T, Lu, L, Zhang, China D.T. "Microstructure and mechanical property of rolled-weld magnesium alloy AZ31", Material and Design, 36, pp: 577-583, 2012.##[17] امیرخانی نجف آبادی،ع. ابراهیمی، ع." بهینه سازی متغیر های فرایند جوشکاری TIG پالسی به منظور بهبود خواص مکانیکی اتصالات جوشکاری شده در آلیاژ منیزیم AZ31"، نشریه ی مهندسی متالورژی ایران.سال بیست و چهارم، ص ص.48-55، سال 1391.##[18] Sq, S, Lj, W,.Korea D.T. "Mechanical properties of Mg alloys welded joints". Weld Technol, 33, pp: 110, 2004. ##[19] M. Hakamada, A. Watazu, Japan D.T-“ Dynamic recrystallization during hot compression of as-cast and homogenized noncombustible Mg–9Al–1Zn–1Ca (in mass%) alloys”- National Institute of Advanced Industrial Science and Technology- Pages 7143–7146-(2010).##[20]T.C. Chang, J.Y. Wang, Taiwan D.T. “Grain refining of magnesium alloy AZ31 by rolling”- Department of Mechanical Engineering- pp 588–591-( 2003).##[21] Chai S , Zhang D. China D.T. ” Influence of post-weld hot rolling on the microstructure and propertis properties of AZ31 magnesium alloy sheet” MaterialsScience&EngineeringA588-208–213(2013).##[22] Cao, X., Immarigeon, J. P., Canada D.T., “A review of laser welding techniques for magnesium alloys” , Journal of Materials Processing Technology, Vol. 171, pp. 188-20, 2006.##[23] Liu, L, Dong, Ch,China D.T. "Gas tungsten-arc filler welding of AZ31 magnesium alloy", Materials Letter, 60, pp: 2194-2197, 2006.##[1] Kulekci. M. K ,. London D.T., “Magnesium and its alloys applications in automotive industry” ,The International Journal of Advanced Manufacturing Technology, Vol. 39, pp 851-865, 2008.##[2] ASM Specialty Handbook, Magnesium and Magnesium Alloys,ASM Int. ,1999.##[3] Lei Z., Jiang Bi, Peng Li, Tao Guo, Yaobang Zhaob, Dengming Zhang, “Analysis on welding characteristics of ultrasonic assisted laser welding of AZ31B magnesium alloy’, Optics and Laser Technology 105 (2018) 15–22##[4] Shaoxing Z,Yang S.,China D.T ,” In Vitro Degradation, Hemolysis and MC3T3-E1 Cell Adhesion of Biodegradable Mg–Zn alloy”, Materials Science and Engineering C, Vol. 29, PP. 1907-1912, 2009.##[5] Yingwei S, Dayong S ., China D.T,” Biodegradable Behaviors of AZ31 Magnesium Alloy in Simulated Body Fluid”, Materials Science and Engineering C, Vol. 29, PP. 1039-1045, 2009.##[6] Wong H M ,Yeung K W.,China D.T,” A Biodegradable Polymer-Based Coating to Control the Performance of Magnesium Alloy Orthopaedic Implants”, Biomaterials, Vol. 31, PP. 2084-2096, 2010.##[7] Dingchuan X,Yeoheung Y,.USA D.T, “Corrosion Protection of Biodegradable Magnesium Implants Using Anodization”, Materials Science and Engineering C, Vol. 31, PP. 215- 223, 2011.## [8] Tuz. L, Kolodziejczak. P, Kolasa. A, "Structure of butt joint of as-cast magnesium alloy", Welding International, 30, pp. 43-47, 2014.##[9] Gou L., Tang A., Pan F., She J., Luo S., Ye J., Shi D., Rashad M. , “ Influence of Sn addition on mechanical properties of gas tungsten arc welded AM60 Mg alloy sheets”, Trans. Nonferrous Met. Soc. China, vol. 26, pp. 2051-2057, 2016.##[10] Asadi, P., Elhami, A., and Kazemi-Choobi K.Iran D.T. , Welding of magnesium alloys. INTECH Open Access Publisher, 2012.##[11] James.A .Toronto D.T ,”Localized corrosion of friction stir spot welds in mangnesium AZ31 alloy” , Materials Science and Engineering, pp.1-98, 2012.##[12] Yunhai.S, Zhengjun.L., China D.T., “Effect Of Magnetic Field on Microstructure and Properties of Magnesium Alloy Welded Joint with GTAW” ., Advanced Materials Research Vols. 189-193 pp 3507-3510, 2011.##[13] Chun M.L, Ching M.C.,China D.T.,“Evolution of microstructures and mechanical properties of AZ31B magnesium alloy weldment with active oxide fluxes and GTAW process”, Journal of the Chinese Institute of Engineers , Vol. 34, No. 8, pp, 1013–1023, 2011.##[14]Senthil Kumar T., Balasubramanian, V., and Sanavullah, M. Y., "Effect of pulsed current TIG welding parameters on tensile properties of AA6061 aluminium alloy", Indian Welding Society. PP. 29-39, (2005).## [15] Gokhale, A. A., Tzavaras, A. A., Brody, H. D., Ecer, G. M., Abbaschian, G. J., and David, S. A.,"Grain Refinement in Castings and Welds", TMS-AIME, Warrendale, PA, p. 223, (2005).##[16] Chen, J, Liu, T, Lu, L, Zhang, China D.T. "Microstructure and mechanical property of rolled-weld magnesium alloy AZ31", Material and Design, 36, pp: 577-583, 2012.##[17] امیرخانی نجف آبادی،ع. ابراهیمی، ع." بهینه سازی متغیر های فرایند جوشکاری TIG پالسی به منظور بهبود خواص مکانیکی اتصالات جوشکاری شده در آلیاژ منیزیم AZ31"، نشریه ی مهندسی متالورژی ایران.سال بیست و چهارم، ص ص.48-55، سال 1391.##[18] Sq, S, Lj, W,.Korea D.T. "Mechanical properties of Mg alloys welded joints". Weld Technol, 33, pp: 110, 2004. ##[19] M. Hakamada, A. Watazu, Japan D.T-“ Dynamic recrystallization during hot compression of as-cast and homogenized noncombustible Mg–9Al–1Zn–1Ca (in mass%) alloys”- National Institute of Advanced Industrial Science and Technology- Pages 7143–7146-(2010).##[20]T.C. Chang, J.Y. Wang, Taiwan D.T. “Grain refining of magnesium alloy AZ31 by rolling”- Department of Mechanical Engineering- pp 588–591-( 2003).##[21] Chai S , Zhang D. China D.T. ” Influence of post-weld hot rolling on the microstructure and propertis properties of AZ31 magnesium alloy sheet” MaterialsScience&EngineeringA588-208–213(2013).##[22] Cao, X., Immarigeon, J. P., Canada D.T., “A review of laser welding techniques for magnesium alloys” , Journal of Materials Processing Technology, Vol. 171, pp. 188-20, 2006.##[23] Liu, L, Dong, Ch,China D.T. "Gas tungsten-arc filler welding of AZ31 magnesium alloy", Materials Letter, 60, pp: 2194-2197, 2006. ##

ارزیابی ریزساختار ورفتار خوردگی اتصالات غیر مشابه لیزری سوپرآلیاژ پایه نیکل 625به فولاد زنگ نزن فریتی 430 Evaluation of microstructure and corrosion behavior of dissimilar laser joint between Inconel 625 and AISI 430 ferritic stainless steel 1 1 در این پژوهش، ریزساختار و خواص خوردگی جوشکاری غیرمشابه سوپر آلیاژ اینکونل 625 به فولاد زنگنزن فریتی 430 با استفاده از لیزرNd:YAGضربانی با توان متوسط 700 وات به‌صورت اتصال لبه روی‌هم مورد بررسی قرار گرفت.فولادهای زنگنزن آستنیتی نسبت به فولادهای فریتی گران‌قیمت‌تر است و لذا با توجه به اینکه فولادهای زنگ نزن فریتی دارای خواص مغناطیسی هستند و قیمت بسیار کمتری دارند و اگر درجایی نیاز باشد که فلز پایه علاوه بر خواص فولادهای زنگ نزن خاصیت مغناطیسی را نیز داشته باشد در صنعت جایگزین خوبی بجای فولاد آستنیتی است. پس از جوشکاری، ریزساختار مناطق مختلف اتصال بهینه که شامل فلز جوش و مناطق متأثر حرارت بود، با استفاده از میکروسکوپ نوری و میکروسکوپ الکترونی روبشی مورد بررسی قرار گرفت. نتایج حاصل شده نشانگر تشکیل ساختار دندریتی بسیار ظریف در فلز جوش بود که در جهات مختلف بصورت رقابتی رشد کرده اند. در فصل مشترک فلز پایه فولاد زنگ نزن فریتی و فلز جوش رشد اپی‌تکسیال مشاهده شد و در ناحیه متأثر از حرارت اینکونل 625، هیچ تغییری در ابعاد دانه‌ها مشاهده نشد. رفتار الکتروشیمیایی فلز جوش در محلول 5/3% وزنی سدیم کلرید در دمای اتاق با استفاده از پلاریزاسیون پتانسیودینامیک مورد بررسی قرار گرفت. نتایج نشان داد که مقاومت در برابر خوردگی به ترتیب از سمت فلز پایه فولاد زنگ نزن فریتی 430 به سمت اینکونل 625 افزایش مییابد. 2 Dissimilar weld joints between stainless steels and nickel based super alloys are extensively used in petrochemical, gas and oil applications. These joints jave great challenges from metallurgical transformations point of view. In this research, microstructural evolutions and corrosion behavior of laser weld joint between Inconel 625 and AISI 430 ferritic stainless steel were investigated. Ferritic stainless steels are less expensive and have magnetic properties in comparison with austenitic stainless steels. Scanning electron microscope and optical microscope were used in order to study the microstructures of weld metal and heat affected zone. It was found that fine dendritic microstructuresare formed in the weld metal which  isgrown in a competition manner. An epitaxial growth was observed in the interface between AISI base metal and weld metal. No considerable grain growth was observed in the heat affected zone on Inconel 625. Corrosion resistance of weld joint was investigated in 3.5 % wtNaCl solution using potantiodynamic polarization test. It was concluded that corrosion resistance is increased from AISI 430 base metal toward Inconel 625 base metal.   103 121 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/282020/02/92018/10/102020/01/28 1398/11/8 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/282020/02/92018/11/182020/01/28 1398/11/8 محمد عمادی M. Emadi مرکزتحقیقات موادپیشرفته،دانشکده مهندسی مواد،واحدنجف آباد،دانشگاه آزاداسلامی، نجف آباد، ایران ایران حسین مستعان H. Mostaan گروه مهندسی مواد و متالورژی، دانشکده فنی و مهندسی، دانشگاه اراک، ایران ایران مهدی رفیعی M. Rafiei مرکزتحقیقات موادپیشرفته،دانشکده مهندسی مواد،واحدنجف آباد،دانشگاه آزاداسلامی، نجف آباد، ایران ایران AISI 430 ferritic stainless steel Inconel 625 Corrosion properties Metallurgical features ND:YAG laser. فولاد زنگ نزن فریتی 430 اینکونل 625 خواص خوردگی خواص متالورژیکی جوش لیزرNd:YAG. ##[1] M.J. Donachie, S.J. Donachie, “Superalloys ATechnical Guide”, 2nd Edition, ##ASM International, 2002 .##[2] C.T.Simsand, W.C.Hugel ed,” The Superalloys Wiley”, 1972.##[3] D.Charre, The Microdtructure of Superalloys, First Edition ,Gordon and Breach Since Publisher, France, Amsterdam,1989##[4] Shakil,M. Amad,M. Hasan,B.A. lqbal,M, “Microstructure and hardness studies of electron beam welded Inconel 625 and stain less steel 304L” , Vacuum, Vol.110, pp.121-126, 2014.##[5] Kou S.” Welding metallurgy. Wiley”,. pp. 383–6 , 1987##[6] Folkhard E.” Welding metallurgy of stainless steels”. New York,Spring-Verlag Wien; 1988##[7] Devendranath Ramkumar,K . Oza,S. Arivazhagan,N ” Investigations on the structure Property relationships of electron beam welded Inconel 625 and UNS 32205” , Materials and Design, Vol.68, pp.158-166, 2015.##[8] Li,Gang . Hang,J . W,Yixiong , ” An investigation on microstructure and properties dissimilar welded Inconel 625 and SUS 304 using high – power CO2 Laser”, int j adv Manuf Technol, Vol.76, pp.1203-1214, 2015.##[9]. John C. Lippold and Damian J .Kotecki., Welding Metallurgy and weldability of Stainless Steels,.published simultaneously in Canada,2005##[10]. Lokesh Kumar G, Karthikeyan.P, Narasimma Raj.C, Prasanna.B, George Oliver” Microstructure and Mechanical Properties of ass (304)-fss (430) Dissimilar joints in smaw & gtaw process” International Journal of Engineering Sciences & Research Technology, ,Vol. 6, pp. 367-378, 2015##[11].M.o.h. amuda , S. Mridha,”Microstructural features of aisi 430 ferritic stainless steel (fss) weld produced under varying process parameters”Department of Manufacturing and Materials engineeringInternational journal of Mechanical and materials engineering (ijmme), Vol. 4, pp. 160-166, 2009.##[12]. 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بررسی تاثیر دما بر رفتار خوردگی اتصال مشابه جوشکاری شده آلیاژ تیتانیومTi-6Al-4Vبه روش اصطکاکی همزنی Investigation of the effect of temperature on the corrosion behavior of welded joints similar of titanium alloy Ti-6Al-4V by friction stir welding method 1 1 در این تحقیق رفتار خوردگی اتصال آلیاژ Ti-6Al-4V به روش جوشکاری اصطکاکی همزنی  با سرعت چرخش 375 دور بر دقیقه و سرعت پیشروی 100 میلمتر بر دقیقه مورد بررسی قرار گرفت. جوشکاری این آلیاژ زیر دمای دگرگونی β انجام شد که متشکل از ساختار هم‌محور در ناحیه همزنی است. رفتار خوردگی این آلیاژ جوشکاری شده در محلول‌ NaCl 5/3% در دماهای 37،25 و 80 درجه سانتیگراد مورد بررسی قرار گرفت. منحنی‌های پتانسیودینامیک در محلول NaCl 5/3% در دمای 80 درجه سانتیگراد یک رفتار گذار رویین و فعال را نشان دادند. تجزیه و تحلیل سطوح نمونه‌ها پس از انجام آزمون‌های الکتروشیمیایی توسط میکروسکوپ الکترونی روبشی (SEM) نشان داد که در این آلیاژ، فاز β به طور عمده در هر سه دمای مذکور خورده شده است، با این حال، میزان این خوردگی در نمونه های مربوط به دمای 80 درجه سانتیگراد بیشتر می‌باشد. 2 In this study, corrosion behavior of Ti-6Al-4V titanium alloy joint by friction stir welding with a rotational speed of 375 rpm and a travel speed of 100 mm/min was investigated. The welding procedure was carried out under β-transus temperature that was consisted of equiaxed grains in the stir zone. The corrosion behavior of the welded joint was investigated in 3.5% NaCl solution at temperatures of 25, 37 and 80 . Microstructure investigation of sample surfaces after electrochemical experiments was conducted using SEM. results revealed that the β phase was mainly corroded at all three testing temperatures, however the corrosion in the sample tested at 80 °C was more considerable. 123 134 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/282020/02/92018/10/102020/01/282020/01/29 1398/11/9 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/282020/02/92018/11/182020/01/282020/01/29 1398/11/9 محمد چیانی M. Chiani دانشجوی دکتری مواد پردیس دانشگاه صنعتی اصفهان ایران مسعود عطاپور M. Atapour دانشیار دانشکده مواد دانشگاه صنعتی اصفهان ایران Friction Stir welding Ti-6Al-4V Corrosion Potentiodynamic جوشکاری اصطکاکی همزنی Ti-6Al-4V خوردگی پتانسیودینامیک. ##1-Boyer R., Welsch G. CEW. Materials Properties Handbook - Titanium Alloys-ASM International. ASM International; 2007.##2-Chattoraj I. Stress corrosion cracking (SCC) and hydrogen-assisted cracking in titanium alloys. Stress Corros. Crack. Theory Pract, pp381–408, 2011.##3-Ahmad Z. Principles of Corrosion Engineering and Corrosion Control,. First. Butterworth-Heinemann Elsevier; 2006.##4-Shibata T, Zhu Y-C. The effect of film formation conditions on the structure and composition of anodic oxide films on titanium. Corros. Sci. [Internet] [cited 2018 Nov 23];37, pp 253–270, .1995.##5-Moiseyev VN. Titanium Alloys: Russian Aircraft and Aerospace Applications. 1st ed. Anim. Behav. CRC; 2005.##6-T.J. Lienert. Microstructure and Mechanical Properties of Friction Stir Welded Titanium Alloys" Friction Stir Welding and Processing. Materials Park, OH: ASM International; 2007.##7-Rondelli G, Vicentini B, Cigada A. The corrosion behaviour of nickel titanium shape memory alloys. Corros. Sci.;30, pp 805–812, 1990.##8-PETERSON, M. H.; BROWN, B. F.; NEWBEGIN, R. L.; GROOVER RE. Stress Corrosion Cracking of High Strength Steels and Titanium Al in Chloride Solutions at Ambient Temperature. CORROSION. 23, pp 142–148, 1967.##9-X.G. Zhang and J. Vereecke. Stress corrosion cracking mechanism of Ti-6Al-4V in acidic methanol. Corrosion.;46, pp 136–141, 1990.##10-Matthew J. Donachie J. Titanium_ A Technical Guide. ASM; 2000.##11-Pilchak AL, Young AH, Williams JC. Stress corrosion cracking facet crystallography of Ti-8Al-1Mo-1V. Corros. Sci.;52, pp 3287–3296, 2010.##12-Atapour M, Pilchak AL, Frankel GS, et al. Corrosion behavior of friction stir-processed and gas tungsten arc-welded Ti-6Al-4V. Metall. Mater. Trans. A Phys. Metall. Mater. Sci.;41, pp 2318–2327, 2010.##13-George F. Vander Voort. METALLOGRAPHY PRINCIPLES AND PRACTICE. Fourth. ASM Int. ASM International; 2007.##14-Grabovetskaya GP, Melnikova EN, Kolobov YR, et al. Evolution of the structural and phase states of a Ti-6Al-4V alloy in forming submicrocrystalline structure with the use of temporary hydrogenation. Russ. Phys. J.;49, pp 442–447, 2006.##15-Elmer JW, Palmer TA, Babu SS, et al. In situ observations of lattice expansion and transformation rates of α and β phases in Ti-6Al-4V. Mater. Sci. Eng. A.. p. 104–113, 2005.##16-Lütjering G, Williams JC. Engineering Materials and Processes: Titanium. 2nd, editor. Springer-Verlag Berlin Heidelb. Springer-Verlag Berlin Heidelberg; 2007.##17-Gammon LM, Briggs RD, Packard JM, et al. Metallography and Microstructures of Titanium and its Alloys. ASM Handb. 2004.##18-Zhang Y, Sato YS, Kokawa H, et al. Microstructural characteristics and mechanical properties of Ti-6Al-4V friction stir welds. Mater. Sci. Eng. A.;485:448–455, 2008.##19-Kitamura K, Fujii H, Iwata Y, et al. Flexible control of the microstructure and mechanical properties of friction stir welded Ti – 6Al – 4V joints. Mater. Des. [Internet].;46:348–354, 2013.##20-Davies PS, Wynne BP, Rainforth WM, et al. Development of microstructure and crystallographic texture during stationary shoulder friction stir welding of Ti-6Al-4V. Metall. Mater. Trans. A Phys. Metall. Mater. Sci.;42:2278–2289, 2011.##21-HUMPHREYS, F.J. MH. RECRYSTALLIZATION AND RELATED ANNEALING PHENOMENA. 2th ed. Elsevier. 2004.##22-Mashinini PM, Dinaharan I, David Raja Selvam J, et al. Microstructure evolution and mechanical characterization of friction stir welded titanium alloy Ti–6Al–4V using lanthanated tungsten tool. Mater. Charact. [Internet].;139:328–336, 2018.##23-Yoon S, Ueji R, Fujii H. Microstructure and texture distribution of Ti-6Al-4V alloy joints friction stir welded below β-transus temperature. J. Mater. Process. Technol. [Internet].;229:390–397, 2015.##24-Yu SY, Scully JR. Corrosion and Passivity of Ti-13 % Nb-13 % Zr in Comparison to Other Biomedical Implant Alloys.;53:965–976, 1997.##25-Ronald W. Schutz. Corrosion of Titanium and Titanium Alloys. Edited by Stephen D. Cramer Bernard S. Covino J, editor. ASM INTERNATIONAL; 2005.##26-Atapour M, Pilchak AL, Shamanian M, et al. Corrosion behavior of Ti-8Al-1Mo-1V alloy compared to Ti-6Al-4V. Mater. Des.;32:1692–1696, 2011. ##

جوشکاری لیزر غیرهمجنس سیمهای ارتودنسی آلیاژ حافظه دار NiTi به فولاد زنگ نزن آستنیتی Dissimilar laser welding of NiTi shape memory alloy to austenitic stainless steel archwires 1 1 در این پژوهش اتصال غیرهمجنس سیمهای ارتودنسی آلیاژ حافظه دارNiTi به فولاد زنگ نزن آستنیتی AISI 304 بررسی شده است. به این منظور، سیم‌های ارتودنسی رایج با سطح مقطع مستطیلی و ابعاد (635/0 × 432/0 میلی متر) انتخاب و از تکنیک جوشکاری لیزر برای اتصال سیمها استفاده شد. ریزساختار اتصالهای بدست آمده با استفاده از میکروسکوپ نوری(OM)، میکروسکوپ الکترونی روبشی (SEM) مجهز به آنالیز EDS و آنالیز پراش پرتو ایکس در مقیاس میکرو (Micro-XRD) بررسی شد.  همچنین از تکنیک میکرو سختی سنجی ویکرز برای ارزیابی خواص مکانیکی منطقه جوش استفاده شد. بررسی‌های ریزساختاری نشان داد، ریزساختار حاصل از جوش لیزر این دو آلیاژ دارای ساختار دندریتی و غیرهمگن می‌باشد.تشکیل ترکیبات بین فلزی تردFe2Ti، Cr2Ti، TiNi3 و Ti2Ni در حین جوشکاری باعث افزایش سختی منطقه جوش تا حدود 800 ویکرز شد. مشاهده شد تشکیل ترکیبات بین فلزی Fe2Ti عمدتا در منطقه جوش مجاور فصل مشترک ذوب فلز پایه NiTi علت اصلی افزایش شدید سختی این منطقه و درنتیجه تمرکز تنش، تشکیل میکروترک و افت خواص مکانیکی می‌باشد. بنابرین یک فرآیند اصلاحی مناسب برای کنترل ترکیب شیمیایی منطقه جوش و بهبود خواص اتصال غیر همجنس این دو آلیاژ نیاز می‌باشد. 2 In this research, dissimilar welding of NiTi shape memory alloy to AISI 304 austenitic stainless steel Archwires was investigated. For this purpose, common straight orthodontic archwire with rectangular cross-section and dimensions of (0.635 × 0.432 mm) were selected and the laser welding technique was used to connect the wires. The microstructure, chemical composition and phasesin the weld zone of the joints werestudied with Optical microscopy (OM), Scanning electron microscopy (SEM) equipped with EDS analysis system, focused X-ray diffraction (Micro-XRD).Also, the mechanical properties of the weld zone were investigated by using Vickers microhardness test. Microstructure investigation showed that the obtained microstructure from the laser weld of these alloys has a dendritic and non-homogeneous structure. According to XRD analysis, brittle intermetallic compounds such as Fe2Ti, Cr2Ti, TiNi3, and Ti2Ni wereformed during laser welding in the weld zone. Formation of these brittle intermetallics caused increasing the hardness of the weld zoneabout 800 HV. and decreasing the mechanical properties. Also, Fe2Ti intermetallic particles mainly formed in the weld region near the NiTi fusion zone which results in stress concentration, micro-cracks formation and dropping joints mechanical properties. Therefore, a suitable modification process is required to control the chemical composition of the weld zone and improving the joint properties of dissimilar laser welded archwires of these alloys. 135 146 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/282020/02/92018/10/102020/01/282020/01/292020/01/29 1398/11/9 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/282020/02/92018/11/182020/01/282020/01/292020/01/29 1398/11/9 سعید اسدی S. Asadi دانشکده مهندسی مواد، دانشگاه صنعتی سهند، تبریز، ایران ایران توحید سعید T. Saeid دانشکده مهندسی مواد، دانشگاه صنعتی سهند، تبریز، ایران ایران علیرضا والانژاد A. Valanezhad دانشکده علوم دندانپزشکی، دانشگاه دانشگاه ناکاساکی، ناکاساکی، ژاپن ژاپن جعفر خلیل علافی J. Khalil Allafi مرکز تحقیقات مواد پیشرفته، دانشکده مهندسی مواد، دانشگاه صنعتی سهند، تبریز، ایران ایران NiTi alloy Austenitic stainless steel Orthodontic archwire Laser welding Intermetallic compounds. آلیاژ NiTi فولاد زنگ نزن آستنیتی سیم ارتودنسی اتصال لیزر ترکیبات بین فلزی. ##[1] Hall PC. Method of welding titanium and titanium based alloys to ferrous metals. Google Patents; 2005.##[2] Otsuka K. Wayman Shape Memory Materials. Cambridge University Press; 1998.##[3] Predki W, Knopik A, Bauer B. Engineering applications of NiTi shape memory alloys. Materials Science and Engineering: A. 2008;481:598-601.##[4] Otsuka K, Ren X. Physical metallurgy of Ti–Ni-based shape memory alloys. Progress in materials science. 2005;50:511-678.##[5] Jani JM, Leary M, Subic A, Gibson MA. A review of shape memory alloy research, applications and opportunities. Materials & Design (1980-2015). 2014;56:1078-113.##[6] Fukumoto S, Inoue T, Mizuno S, Okita K, Tomita T, Yamamoto A. Friction welding of TiNi alloy to stainless steel using Ni interlayer. Science and Technology of Welding and Joining. 2010;15:124-30.##[7] Shinoda T. Functional Characteristics of Friction Welded Near-equiatomic TiNi Alloy. Transactions of the Japan Welding Society. 1991;22:30-6.##[8] Ikai A, Kimura K, Tobushi H. TIG welding and shapememory effect of TiNi shape memory alloy. Journal of Intelligent Material Systems and Structures. 1996;7:646-55.##[9] van der Eijk C, Fostervoll H, Sallom ZK, Akselsen OM. Plasma welding of NiTi to NiTi, stainless steel and hastelloy C276. of the ASM Materials Solutions Conference2003. p. 125-9.##[10] Ng C, Mok ES, Man H. Effect of Ta interlayer on laser welding of NiTi to AISI 316L stainless steel. Journal of materials processing technology. 2015;226:69-77.##[11] Matsunaga J, Watanabe I, Nakao N, WatanabeE, Elshahawy W, Yoshida N. Joining characteristics of titanium-based orthodontic wires connected by laser and electrical welding methods. 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تعیین تجربی اثر کربوره کردن بر استحکام کششی، مقاومت به ضربه، خستگی و تنش پسماند نانوساختار سازی جوش سربه سر فولاد میکروآلیاژی Experimental determination of the carburizing effect on tensile strength, impact strength, fatigue, residual stress of nano girth welding on microalloy steel 1 1 در این مقاله، عملیات حرارتی کربوره کردن بر روی جوش حاوی نانو اکسید تیتانیوم و نانو کاربید تیتانیوم  (فولاد گرید ایکس 65 خطوط انتقال گاز) انجام شد. نتایج شارپی نشان میدهد، در نمونۀ کربوره شده حاوی نانوذرات اکسید تیتانیوم و نانو ذرات کاربید تیتانیوم نسبت به نمونۀ بدون عملیات حرارتی (حاوی نانوذرات اکسید تیتانیوم و کاربید تیتانیوم)، به ترتیب 6 و 42 درصد افزایش پیدا کرده است. همچنین، استحکام نهایی نمونۀ کربوره شده حاوی نانوذرات اکسید تیتانیوم و کاربید تیتانیوم نسبت به نمونۀ بدون عملیات حرارتی (نانوذرات اکسید تیتانیوم و کاربید تیتانیوم) به ترتیب 20 و 28 درصد افزایشیافته است. نتایج نشان میدهد، در هردو نمونه کاربوره شده نانو آلیاژی میزان عمر خستگی افزایشیافته است. همچنین، میزان عمر خستگی در نمونۀ تمپر شده نانوذرات کاربید تیتانیوم نسبت به اکسید تیتانیوم، افزایش بیشتری داشته است. نتایج آزمون خستگی نشان می‌دهد، در نمونۀ کربوره شده حاوی نانوذرات کاربید تیتانیوم نسبت به نمونۀ کربوره شده حاوی نانوذرات اکسید تیتانیوم، میزان عمر خستگی (بار 150 نیوتن) به میزان 20 درصد افزایش پیدا کرده است. در این بارگذاری عمر خستگی (نمونۀ کربوره شده حاوی نانوذرات کاربید تیتانیوم نسبت به نمونۀ بدون عملیات حرارتی) 31 درصد افزایشیافته است.نتایج نشان میدهد، در هردو نمونه کربوره شده نانو آلیاژی میزان عمر خستگی افزایشیافته است نتایج آزمون کرنش سنجی سوراخ  نشان میدهد، در نمونۀ کربوره شده حاوی نانوذرات اکسید تیتانیوم و کاربید تیتانیوم نسبت به نمونۀ بدون عملیات حرارتی (نانوذرات اکسید تیتانیوم و کاربید تیتانیوم)، تنش پسماند محیطی به ترتیب 9 و 6 درصد کاهش پیدا کرده است. 2 In this article the effects of carburizing heat treatment on girth weld with containing titanium oxide and titanium carbide nanoparticles (X-65 grade of gas pipeline) is evaluated. The charpy results show that in the carburized sample containing titanium oxide and titanium carbide nanoparticles compared to the no heat treatment sample (containing titanium carbide and titanium carbide nanoparticles), has been respectively increased by 6% and 42%. Also, the ultimate strength carburized sample containing titanium oxide nanoparticles and titanium carbide nanoparticles compared to the no heat treatment sample (containing titanium oxide and titanium carbide nanoparticles) has been respectively increased by 20% and 28%. The results show that the fatigue life in both carburized nano-alloy samples has been increased. The fatigue life in the carburized sample of titanium carbide nanoparticles has increased more than that of titanium oxide nanoparticles. The fatigue test results show that in the carburized sample containing titanium carbide nanoparticles compared to the tempered sample containing titanium oxide nanoparticles, fatigue life (150-N force) has been increased by 20%. In this loading the fatigue life (tempered sample containing titanium carbide nanoparticles compared to the no heat treatment sample) has been increased by 31%. The results show that the residual stress in both carburized nano-alloy samples has been decreased The hole drilling strain gage results show that in the tempered sample containing titanium oxide oxide nanoparticles and titanium carbide nanoparticles compared to the no heat treatment sample (containing titanium oxide nanoparticles and titanium carbide nanoparticles), hoop residual stresses has been respectively decreased by 9% and 6%.   147 155 2017/06/82020/01/282018/03/92018/06/212018/07/92020/01/282020/02/92018/10/102020/01/282020/01/292020/01/292020/01/29 1398/11/9 2018/12/62020/01/282019/04/72018/11/182018/09/122020/01/282020/02/92018/11/182020/01/282020/01/292020/01/292020/01/29 1398/11/9 مجید سبک روح M. Sabokrouh استادیار، دانشکده مهندسی، مرکز آموزش عالی محلات، محلات ایران Nano-Welding Carburizing Fatigue Residual stress Impact strength. نانو جوشکاری کربوره کردن خستگی تنش پسماند مقاومت به ضربه. ##[1] Y. Wanga, Z. Yangb, F. Zhangab, D. Wua, Microstructures and mechanical properties of surface and center of carburizing 23Cr2Ni2Si1Mo steel subjected to low-temperature austempering, Materials Science and Engineering: A, Vol. 60 , pp. 166-177, 2016.##[2] Q.Taoa, J. Wanga, L. Fub, Z. Chena, C. Shena, D. Zhanga, Z. Suna, Ultrahigh hardness of carbon steel surface realized by novel solid carburizing with rapid diffusion of carbon nanostructures, Journal of Materials Science & Technology, Vol. 33, pp. 1210-1218, 2017.##[3] B. Beidokhti, A. H. Koukabi, A. Dolati, Effect of titanium addition on the microstructure and inclusion formation in submerged arc welded high strength alloy pipeline steel, Journal of Materials Processing Technology, Vol. 209, pp. 4027–4035, 2009.##[4] A. Chabok, K. Dehghani, M. Ahmadi Jazani, Comparing the Fatigue and Corrosion Behavior of Nanograin and Coarse-Grain IF Steels, Acta Metallurgica Sinica, Vol. 28, pp. 295-301, 2014.##[5] K. Muszka, J Majta, P. D. Hodgson, Modeling of the Mechanical Behavior of Nanostructured HSLA Steels, ISIJ International, Vol. 47, pp. 1221–1227, 2007.##[6] S. H. Hashemi, M. Sabokrouh, M. R. Farahani, Investigation of welding in multi-pass girth welding of thermomechanical steel pipe, Modares Mechanical Engineering, Vol. 13, No. 4, pp. 60-73, 2013. ##[7] M. Sabokrouh, S. H. Hashemi, M. R. Farahani, Experimental study of the weld microstructure properties in assembling of natural gas transmission pipelines, Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, Vol. 231, No. 6, pp. 1039-1047, 2017.##[8] M. Sabokrouh, M. R. Farahani, Experimental study of the residual stresses in girth weld of natural gas transmission pipeline, Journal of Applied and Computational Mechanics, Available Online from 13 July 2018.##[9] M. Sabokrouh, M. R. Farahani, Simulation of the residual stresses distribution in girth weld of gas transmission pipeline, Modares Mechanical Engineering, Vol. 19, No. 1, pp. 223-228, 2019. ##[10] M. Sabokrouh, M. R. Farahani, Mathematical modeling of residual stress distribution in girth welding of high strength low alloy steel gas pipelines, Modares Mechanical Engineering Vol. 18, No. 4, pp. 990-996, 2018. ##[11] M. Sabokrouh, b. khoshsima, Experimental determination of the effect of titanium nanoalloy on mechanical properties of girth welding on Iranian natural gas transmission pipelines, Journal of Solid and Fluid Mechanics, Available Online from 3 november 2018.##[12] M. Sabokrouh, Experimental determination of the effect of titanium nanoalloy on residual stress of girth welding on Iranian natural gas transmission pipelines,Journal of Solid and Fluid Mechanics, Under Review, 2018. ##[13] M. Sabokrouh, Experimental determination of the effect of titanium nanoalloy on fatigue of girth welding on Iranian natural gas transmission pipelines, Modares. ##