Ti6321合金激光-MIG复合焊接接头组织和力学性能分析

Microstructure and Mechanical Properties of Laser-MIG Hybrid Welded Joint of Ti6321 Titanium Alloy

对6 mm厚的Ti6321钛合金板开展激光-MIG复合焊接试验,对焊接接头的微观组织和力学性能进行了测试分析。结果表明,焊缝区金相组织主要为粗大的β柱状晶和细小的针状α’相形成的网篮组织;热影响区金相组织分布不均匀,近焊缝区组织主要由针状马氏体α’相和等轴α相组成,而近母材区组织主要由等轴α相、针状马氏体α’相和少量残余β相组成。拉伸断裂发生在远离焊缝的母材处,抗拉强度均值为935 MPa。焊缝和热影响区的硬度明显高于母材,最高硬度值出现在熔合线附近。

Laser-MIG hybird welding experiment was carried out for 6 mm thick Ti6321 titanium alloy plate,and the microstructure and mechanical properties of the welded joint were tested and analyzed.The result shows that the microstructure of the weld zone is mainly composed of coarseβcolumnar crystal and fine needle-likeα'phase,and the microstructure of the heat affected zone is not uniform and the microstructure near the weld zone are needle-likeα'phase and equiaxedαphase,there are equiaxedαphase,needle-likeα'phase and a few ofβresidual phase near the base metal.The tensile fracture occurs at the base metal far from the weld,the average tensile strength is 935 MPa.The hardness of the weld and heat-affected zone is obviously higher than that of base metal,and the highest hardness appears near the fusion line.