镁合金激光、激光填丝及激光-电弧复合焊接接头对比分析
Comparison of Laser, Laser Filling and Laser-arc Hybrid Welding of Mg Alloy
高 明1， 张 林2， 林天晓1， 曾晓雁1
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作者单位：1.华中科技大学 光电子科学与工程学院 武汉光电国家实验室, 湖北 武汉 430074； 2.安琪酵母股份有限公司, 湖北 宜昌 443003）
中文关键字：镁合金； 激光焊接； 微观组织； 拉伸性能
英文关键字：magnesium alloy; laser welding; microstructure; tensile properties
中文摘要：系统对比了镁合金单纯激光、激光填丝和激光-电弧复合焊接接头的微观组织及力学性能。试验结果表明，激光焊缝表面有明显的咬边及凹坑缺陷出现；激光填丝及复合焊缝成形良好、均匀规整。在激光功率和焊接速度相同的情况下，激光填丝焊接头的凝固组织最细小，半熔化区最窄；激光-电弧复合焊接头的凝固组织最粗大，半熔化区最宽。拉伸性能测试表明，激光填丝焊接头抗拉强度和伸长率最高，且抗拉强度优于母材；复合焊和单纯激光焊接头的抗拉强度为母材的95%左右。此外，所有接头均表现为韧-脆混合断裂模式。
英文摘要：The weld microstructure and mechanical properties of laser filling and laser-arc hybrid welded joints of AZ31B alloy were compared. The results show that obvious undercut and notch defects are observed in laser welds, while laser filling and hybrid welds show accepted appearance without above defects. As the laser power and welding speed are constant, the laser filling weld has the finest solidification structure and narrowest partial melted zone, while the hybrid weld has the coarsest solidification structure and widest partial melted zone. Both the tensile strength and elongation of laser filling welds are best. The tensile strength of laser filling welds is even higher than that of base metal, while the maximum tensile strength of both laser and hybrid welds are about 95% of base metal. The fracture surface of all the joint is characterized by ductile-brittle mixed fracture.