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.
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。
Microstructures and mechanical properties of friction-stir welding joint of Al-Cu-Li alloy
Abstract:
Friction-stir welds of Al-Cu-Li aluminum rolled sheet material in 2mm thickness were completed and the joint microstructures could be pided 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.