5A06-6063铝合金相对位置对搅拌摩擦焊接头组织及性能的影响

摘要

Dissimilar materials 5A06 and 6063 aluminum alloy in 4 mm-thickness were joined by friction stir welding.The influence of relative location of base metals on the weld appearance, microstructure and mechanical property of joint was mainly investigated. Experimental results show that when the 6063 aluminum alloy is placed on the advancing side:the formation of joint is pretty good because base metal flow fully and mix uniformly; the heat affected of advancing side gets a finer grain comparing with grain in the heat affected of retreating side when the 5A06 aluminum alloy is placed on the advancing side, the material in the nugget zone form fine equiaxed grains devoleped by dynamic recrystallization;the hardness distribution of joint is "W" shape,but the fluctuation of hardness of the heat affected zone and nugget zone is smaller than that of 6063 aluminum alloy of retreating side,and the minimal hardness in the heat affected of advancing side is also higher;the tensile strength of the joint is higher than that of 5A06 aluminum alloy of advancing side;the ductile dimple and torn edges are mainly micro feature of the fracture surface.%对4 mm厚的5A06和6063铝合金进行搅拌摩擦焊对接试验,主要研究异种铝合金母材相对位置对接头成形、组织及力学性能的影响.实验结果表明:当6063铝合金固定在前进侧时,母材流动充分、混合均匀,接头质量优良；前进侧热影响区晶粒比其固定在后退侧相应位置的晶粒更细,焊核区发生动态再结晶过程,形成细小等轴的晶粒；接头硬度分布规律呈“W”型,但焊核区和热影响区的硬度比其置于后退侧的硬度波动要小,并且前进侧热影响区最低硬度值也更高；接头抗拉强度比5A06铝合金在前进侧时要高,断口微观形貌呈韧窝状并有撕裂棱.