稀土镁合金GW103K光纤激光焊接工艺研究及优化

Research and optimization of GW103K fiber laser welding procedure for rare earth magnesium alloy

采用光纤激光焊对T6态GW103K板材进行焊接,建立了焊接工艺窗口,并采用正交试验设计方案,以高温抗拉强度为评价指标,运用极差法和方差法优化焊接工艺参数,确定了各工艺参数的影响程度及最优焊接工艺。研究激光功率对接头高温力学性能的影响,分析最优工艺参数下焊接接头高温力学性能及高温拉伸断口形貌。结果表明:激光功率对焊接接头高温力学性能影响最为显著。最优工艺参数下,焊接接头200℃平均高温抗拉强度为281.1 MPa,为母材的86.3%,延伸率为7.4%,达到母材的65.4%;该参数下接头成形良好,焊缝区域晶粒尺寸较小;此时接头与母材断裂模式均为韧性断裂。

The fiber laser welding is used to weld the T6 state Mg-10 Gd-3 Y-0.5 Zr plate for creating welding procedure window. The welding parameters are optimized by orthogonal experimental design method with the high temperature tensile strength of welded joints as the evaluation index. The optimal welding parameters are achieved by range analysis and variance analysis,and the degree of influence of each welding parameter and optimum welding procedure are determined. The effect of laser power on the high temperature mechanical properties of the welded joint is studied. The high temperature mechanical properties and high temperature tensile fracture morphology of welded joints under the optimal welding parameters are analyzed.The result shows that the laser power has the most significant influence on the high temperature mechanical properties of the welded joint. Under the optimal welding parameters,the average tensile strength of the welded joint at 200 ℃ is 281.1 MPa,which is 86.3% of the base metal,and the elongation is 7.4%,which is 65.4% of the base metal. And the joint is well formed,the grain size in the weld metal zone is small,and the fracture mode of the base metal and the joint both are ductile fracture.