银中间层对钢/铝激光双道焊接头组织与性能的影响

Effect of silver interlayer on microstructure and properties of steel/aluminum laser welding joint

对钢/铝接头直接采用激光焊接时,接头极易产生脆性Fe-Al金属间化合物。针对该问题,采用激光双道焊接方法研究了银中间层对304不锈钢/6061铝合金焊接接头微观组织及力学性能的影响。结果表明,预置银为中间层,采用双道激光焊接工艺,焊后接头成形良好;组织分析表明,焊缝区域明显分为靠近铝侧的区域A和靠近钢侧的区域B,区域A由富银相和富铝相混合组成,区域B由纯银(区域B1)和奥氏体相(区域B2)组成。此外,焊缝中未出现脆性Fe-Al金属间化合物。力学性能测试结果显示,断裂发生在接头处的纯银区,抗拉强度为175.59 MPa,断后伸长率约为3%。

When laser welding is directly used for steel/aluminum joints, brittle Fe-Al intermetallic compounds are easily produced. For the issue, the effects of silver interlayer on microstructure and mechanical properties of 304 stainless steel/6061 aluminum alloy welded joint were investigated by utilizing double laser weldi ng in the paper. The results of the research showed that the interlayer was the prefabricated by silver, and the joint was formed well by dual laser welding process. Organizational analysis showed that the weld area was obviously divided into area A near the aluminum side and area B near the steel side. Area A was a silver-rich phase mixed with aluminum-rich phase, and area B was made from pure silver zone(B1) and austenitic zone(B2). In addition, Fe-Al brittle intermetallic compounds didn’t appear in the weld seam. The results of mechanical properties showed that the fracture occurred in the pure silver zone of the joint, and the tensile strength was175.59 MPa, and the elongation after fracture was about 3%.