ZK60镁合金光纤激光焊接工艺参数及接头性能研究

目的 采用光纤激光对ZK镁合金进行焊接，分析焊接工艺参数对焊接接头性能的影响规律。方法 采用正交实验方法，在焊接过程中对焊接主要的工艺参数比如:激光的功率，焊接的速度，离焦量进行三因素三水平正交实验，采用拉力实验机对焊接接头进行抗拉强度测试，得到抗拉强度最大的工艺参数组合。对焊缝微观组织及断口形貌进行分析。结果 当激光功率为1 400 W、焊接速度为40 mm/s、离焦量为3 mm时，焊缝抗拉强度达到最高的308 MPa，达到母材抗拉强度的95%。结论 在合适的工艺条件下，光纤激光焊接过程中，如果热输入较低，焊接速度过快，导致熔池冷却速度非常快，同时细化了晶粒，提高焊缝接头的综合力学性能。

Technology and Joint Performance Research of Fiber Laser Welded ZK60 Magnesium Alloy

ZK60 magnesium alloy was welded by fiber laser, and the influence of welding parameters on the properties of welded joints was analyzed. The orthogonal experiment method with laser power, welding speed and defocus amount was carried out. The tensile strength of the welded joints was tested by tensile test machine, and the maximum tensile strength was obtained. The microstructure and fracture morphology of weld were analyzed. When the laser power was 1 400W, the welding speed was 40 mm/s, and the defocus was 3 mm, the tensile strength of the weld reached to the highest of 308 MPa, which was 95% of the tensile strength of the base metal. Under the suitable process conditions, the heat input of fiber laser welding was low, the welding speed was fast, the cooling rate of molten pool was fast, the grain was refined, and the comprehensive mechanical properties of weld joints had been improved.