铝/钢微束等离子熔钎焊接头组织及力学性能

采用微束等离子焊接方法进行6010铝合金/镀锌钢对接熔钎焊工艺试验，在合适的工艺参数下获得成形良好的铝/钢熔钎焊对接接头，采用金相显微镜、扫描电子显微镜、能谱仪、拉伸试验机等多种测试手段对所得接头形貌、微观组织及力学性能进行分析. 结果表明，所得接头焊缝正、背面铺展良好，无气孔、裂纹、夹渣等明显缺陷，为典型的铝/钢熔钎焊对接接头；接头界面处形成锯齿状的Fe₂Al₅金属间化合物，且金属间化合物层厚度和焊缝铺展宽度共同决定了接头强度，当焊接电流为38.5 A时，熔钎焊接头抗拉强度为193 MPa，为铝母材的79.8%，接头断裂形式为韧脆混合断裂.

Microstructure and mechanical property of welding-brazing joint between aluminum and steel by micro-beam plasma welding

Butt welding-brazing joint between 6010 aluminum alloy and galvanized steel sheets was obtained by micro-beam plasma welding method. A sound weld joint could be obtained in the suitable welding parameter. The analysis was carried out for the weld joint morphology, microstructure and mechanical property using metallographic microscope, scanning electron microscope, energy-dispersive spectrometer and universal tensile testing machine. The results show that a good spreading width is got in back and front sides of weld joint, there are no obvious crack, pore, slag in the joint, and the joint shows a typical welding-brazing characteristic. The serrated intermetallic compound Fe₂Al₅ is formed at the interface. The joint strength is determined by the thickness of intermetallic compound layer and the spreading width. When the welding current is 38.5 A, the tensile strength of weld joint is 193 MPa, which can reach 79.8% of aluminum base material. The fracture form of joint is ductile-brittle fracture.