铝/钢异种金属电弧辅助激光对接熔钎焊方法

Method of fusion-brazed butt joint between aluminum alloy and galvanized steel by arc-assisted laser

采用小功率TIG焊电弧辅助激光热源进行5A06铝合金和热镀锌钢ST04Z对接熔钎焊工艺试验,获得表面成形连续、美观的焊缝.采用SEM,EDS,XRD,拉伸试验机、显微硬度计对熔钎焊接头的微观组织和力学性能进行了研究.结果表明,与单纯激光相比,电弧辅助激光热源改变了焊接过程的温度场分布,从而促进液态铝向钢侧的铺展,所得对接接头最大抗拉强度可达到163 MPa,约为5A06铝合金母材抗拉强度的74%,是激光焊接头强度的1.3倍.接头过渡层形成的金属间化合物以脆硬的Fe2Al5,Fe4Al13为主.拉伸断裂起始于脆性的金属间化合物层,终止于韧窝断裂.

Butt fusion-brazed joint between SA06 aluminum alloy and ST04 Z steel sheets was obtained by low power arcassisted laser.The welding seam had continuous and beautiful surface appearance.The microstructure and mechanical properties of fusion-brazed butt joint were studied by using SEM,EDS,XRD,tensile testing machine and micro hardness tester.The results show that,compared with a single laser,arc-assisted laser could promote the spreading of liquid aluminum to steel by adding arc heat.The maximum tensile strength of butt joint can reach to 163 MPa,about 74%tensile strength of 5 A06 aluminum alloy,which also is 1.3 times of the single laser-welded joint strength.Intermetallic compounds in transition layer of butt joint were mainly composed of rigid Fe_2Al_5 and Fe_4Al_(13).Tensile failure began in the rigid intermetallic compound layer and ended in tenacious fracture.