RT - Journal Article T1 - Effect of heat treatment on the grain structure and mechanical properties of Al-7075 friction stir weld JF - JWSTI YR - 2016 JO - JWSTI VO - 2 IS - 2 UR - http://jwsti.iut.ac.ir/article-1-95-en.html SP - 27 EP - 37 K1 - Friction-stir welding K1 - Al-7075 K1 - Microstructure K1 - Abnormal grain growth K1 - Mechanical properties AB - The fine grain structure of friction-stir welded aluminum alloys is unstable during post weld heat treatment and some grains abnormally grown. In this study, the sequence of abnormal grain growth during T6 heat treatment of Al-7075 friction-stir weld and its effect on mechanical properties of the weld was studied. The results showed that heat treatment in 510 ˚C resulted in drastic grain growth in stir zone and fine equiaxed grains in the stir zone of as-welded joint were substituted by millimeter-scale irregular grains. Post weld heat treatment resulted in decrease in the tensile elongation from about 10% to 1.5% although the joint tensile strength improved by 28%. In addition, post weld heat treatment changed the fracture location from the heat-affected zone to the stir zone. LA eng UL http://jwsti.iut.ac.ir/article-1-95-en.html M3 ER -