(哈尔滨工业大学 现代焊接生产技术国家重点实验室,
哈尔滨 150001)
摘 要: 采用搅拌摩擦焊方法对2mm厚的Al-Cu-Li合金轧制板进行了焊接。 接头内形成了焊核区、 热机影响区和热影响区。 焊核区由细等轴再结晶组织构成; 热机影响区内的组织发生较大的弯曲变形, 并在热循环的作用下发生了回复反应; 热影响区形成了粗大的板条状组织。 实验结果表明: 在200mm/min的焊接速度下, 接头的拉伸强度最高, 达到393MPa, 断裂形式为韧性和脆性的混合型断裂; 在500mm/min的焊接速度下, 接头强度为267.7MPa, 断裂形式为脆性断裂。
关键字: 搅拌摩擦焊; Al-Cu-Li合金; 接头组织; 力学性能
(State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China)
Abstract: Friction-stir welds of Al-Cu-Li aluminum rolled sheet material in 2mm thickness were completed and the joint microstructures could be divided into there regions, namely, welded nugget zone(WNZ), thermal-mechanically affected zone(TMAZ) and heat affected zone(HAZ). And there are much difference for microstructures among the above three zones: the microstructures within the WNZ, in which dynamic recrystallization occurred, consist of refined, equiaxed grains; those within the TMAZ, in which recovery occurred, consist of highly deformed grains; those within the HAZ consist of coarse lath grains. Mechanical property measurement and fracture analysis demonstrate that the peak tensile strength of the joint is 393MPa at 200mm/min and the fracture mode is ductile/brittle mixed fracture; and at 500mm/min, tensile strength of the joint is 267.7MPa, and the fracture mode is brittle fracture.
Key words: friction-stir welding; Al-Cu-Li alloy; joint microstructures; mechanical property