2219-O铝合金的搅拌摩擦焊接

对2219-O铝合金进行了搅拌摩擦焊接,采用光学显微镜分析了接头的微观组织,采用拉伸试验方法评价了接头的力学性能.微观分析表明,在热机循环的共同作用下,焊核区(WNZ)发生了动态再结晶,形成了细小的等轴晶粒,并且沉淀相的数量较其它各区有所增加;热机影响区(TMAZ)晶粒被拉长、弯曲,发生了动态回复和部分再结晶,晶粒内部开始有新的晶粒生成;热影响区(HAZ)的晶粒发生粗化.力学性能测试结果表明,当转速为800r/min,焊接速度为200～400 mm/min时,接头与母材等强度,断裂发生在母材区;当焊接速度大于400mm/min时,接头的抗拉强度很低,断裂发生在缺陷处.

Friction stir welding of 2219-O aluminum alloy

2219-O aluminum alloy was friction stir welded to investigate the effect of friction stir welding on its microstructure and mechanical properties in this paper.The microstructures of different zones in the joint were analyzed by optical microscopy,and the mechanical properties of the joint were evaluated by means of tensile tests.Microstructural analyses indicated that the weld nugget zone(WNZ) is composed of fine isometric grains because of continuously dynamic recrystallization,and more precipitates formed in this zone.In the thermal mechanical affected zone(TMAZ),the grains have experienced incomplete recrystallization due to seriously plastic deformation,and some small grains begin to nucleate.In the heat affected zone(HAZ),all the grains are coarsened.Tensile tests showed that the tensile strength of the joint is the same as that of the base metal,and the fracture occurs in the base metal when the tool rotation speed was 800 rpm and the welding speed was less than 400 mm/min.On the other hand,when the welding speed was greater than 400 mm/min,the mechanical properties of the joint significantly degrade and the joint fractures at the defect location because of the formation of a defect in the WNZ.