MLZ91镁锂合金激光焊接接头的显微组织与力学性能

Microstructure and Mechanical Properties of MLZ91 Mg-Li Alloy Laser Welded Joints

采用光学显微镜、扫描电镜、拉伸试验机和显微硬度仪等手段研究了MLZ91镁锂合金激光焊接接头的显微组织和力学性能。结果表明,激光焊接的快速熔化和凝固过程可以显著地细化母材粗大的板条状α+β两相组织,由于焊缝组织的细晶强化、过时效软化相θ的消失以及细小均匀分布析出相的弥散强化,对接接头焊缝的力学性能优于母材;搭接接头抗剪切力与搭接面的有效连接尺寸成正比。

The microstructure and mechanical properties of MLZ91 Mg-Li alloy laser welded joints were studied by using optical microscope, scanning electron microscope, tensile equipment and hardness tester. The results show that the rapid melting and solidification process of laser welding can significantly refine the coarse lathe α +β duplex structure of MLZ91base metal;due to the fine grain strengthening of the weld, the disappearance of the over-aging softening phase θ, and the dispersion strengthening of the fine and uniformly distributed precipitates, the mechanical properties of the butt joint weld are better than that of MLZ91 base metal;the shear resistance of lap joints is proportional to the effective connection size of lap surface.