搅拌摩擦焊接中材料变形及残余应力分析

采用数值模拟手段,分析了在搅拌摩擦焊接过程中不同材料的变形情况及其残余应力的分布,研究了材料变形与残余应力之间的关系,并建立了异种金属搅拌摩擦焊接的模型。研究结果表明,搅拌摩擦焊接过程中材料的流动主要集中在焊接构件的后退侧,且在搅拌摩擦焊接过程中铝合金较钢表现出更好的流动性能。残余应力分布呈现典型的双峰特征,残余应力的最大值发生在热影响区的边界。拉伸残余应力较大的区域与等效塑性应变较大的区域具有较好的对应关系。异种金属焊接会增大焊接构件搅拌区内较软材料一侧的残余应力。

Analysis of material deformations and residual stresses in friction stir welding

Numerical method has been used in this paper to analyze the deformations of different materials in friction stir welding process and the residual stress distributions. The relationship between the material deformation and the residual stress distribution is analyzed in details. Numerical model has been created to simulate the joining of dissimilar metals. Compared with the material flow on the advancing side, the material flow is faster on the retreating side of the friction stir welds. The results reveal that the double peak feature of the stress distribution with maximum in the boundaries of the heat affected zones can be observed in this study. The region of the large equivalent plastic strain can correlate well with the one of the large tensile residual stress. The residual stress of the softer metal in the nugget zone can be increased in the joining of the dissimilar metals.