2219铝合金FSW/VPPAW交叉接头组织和性能

Microstructure and mechanical properties of VPPAW to FSW intersection weld of 2219 aluminum alloy

通过沿垂直于搅拌摩擦对接焊缝的方向进行变极性等离子弧对接立焊获得交叉焊缝,研究了6mm厚的2219铝合金交叉焊缝的微观组织和拉伸性能,并利用扫描电镜对焊缝断口的形貌进行了观察。结果表明,交叉焊缝呈现出铸态组织的特征,但是与单纯变极性等离子弧焊焊缝相比组织更不均匀。交叉焊缝的力学性能具有方向性,沿变极性等离子弧焊方向抗拉强度为254.5 MPa,沿搅拌摩擦焊方向的性能是207.53MPa,仅为母材的50%,满足使用要求。气孔是造成焊缝性能降低的主要原因。

The intersection weld of 2219 Aluminum alloy with 6mm thickness was obtained by variable polarity plasma arc welding (VPPAW) to friction stir welding(FSW).The microstructure and tensile strength of intersection weld were studied.The results show that the microstructure of orthogonal cross joints presents in usual characteristics of cast structure.However,compared with the joint made by VPPAW,it is much more asymmetric and is not symmetrical to the center of FSW seam.The tensile strength of intersection weld is directional.In the direction of VPPAW,the tensile strength is 254.5 MPa,which is equal to that of plasma welding joint.In the direction of FSW,the tensile strength is 207.53 MPa,which is just 50 percent of base metal.Gas pore is the main influencing factors on the performance of VPPAW/FSW intersection welds.