2A12铝合金回填式搅拌摩擦点焊接头的组织及性能

Microstructure and Mechanical Properties of Refilled Friction Stir Spot Welded Joints for 2A12 Al Alloy

试验研究了2A12铝合金回填式搅拌摩擦点焊接头的微观组织及力学性能。结果表明:由于焊接不同区域经历不同的焊接热循环与机械搅拌作用,造成焊接区微观组织的不均匀分布。热影响区组织发生长大并且变暗;热机影响区晶粒被拉长变形,组织不均匀;焊核区发生动态再结晶形成细小等轴晶。焊点的剪切拉伸力学性能较好,达9.193k N,韧性断裂特征明显,韧窝呈抛物线状。

The microstructure and mechanical properties of refilled friction stir spot welded joints for 2A 12 Al alloy were studied. The results show that the microstructure is different in the weld zone because of different welding thermal cycles and mechanical stirring action experiencing for different zones. The microstructure at heat affected zone becomes larger and darker while it is elongated and deformed for thermal mechanically affected zone. Refined equiaxed grains are found inside the weld nugget because of the dynamic recrystallization inside the weld centre. The shear tensile strength of 2A12 spot weld is better, which can reach 9.193kN, the fracture analysis shows a ductile fracture mechanism with some parabola shape dimples at fracture surface.