2014铝合金搅拌摩擦焊接头的微观组织及力学性能

采用搅拌摩擦焊方法对8mm厚的2014Al合金进行了焊接,焊后对接头的微观组织和力学性能及断裂特性进行了分析.研究结果表明,焊核区和轴肩影响区由细小的等轴再结晶组织构成;热机影响区受机械和热的双重作用组织发生了较大程度的变形,在热循环的作用下发生回复反应;热影响区仅受热循环的作用,组织稍微有粗化现象.力学试验表明:焊接速度为150mm/min时,接头的抗拉强度可以达到361MPa,为母材的78%,抗弯强度达到母材的76%.断口形貌分析显示,接头断裂模式为韧性和脆性的混合型断裂.

Microstructures and Mechanical Properties of Friction Stir Welding Joint of 2014 Aluminum Alloy

Friction stir welding of 2014 Al alloy in 8 mm thickness has been successfully completed.The metallurgy experiment demonstrates that the FSW joint microstructures could be divided into four different regions and the dynamic recrystallization occurs in the weld nugget and the shoulder affected zone(SAZ),which consist of refined,equiaxed grains.The microstructures in TMAZ,in which recovery occurred,consist of highly deformed grains and those in HAZ consist of coarse wattle grains.Mechanical property measurements demonstrate that the peak tensile strength of the joint can reach 361MPa,as much as 78% of the base metal,and the bend strength can reach 76% of the base metal.The fracture analysis shows that the fracture mode of the joints is ductile/brittle mixed fracture.