镁合金/钛合金脉冲激光焊接头的组织、性能调控

采用脉冲激光偏移镁侧并添加铜中间层的方法对镁合金和钛合金进行激光对接焊接,研究了界面元素扩散和反应特点,分析了铜中间层厚度对接头组织和力学性能的影响及接头断裂的主要原因。结果表明:铜中间层的加入改善了焊缝/钛合金界面的组织,增大了界面附近Ti-Cu化合物的含量;随着铜中间层厚度增大,界面处Ti2Cu反应层的厚度逐渐增大并变得连续,且接头的断裂位置从界面反应层转变到焊缝区;当铜中间层的厚度达到30μm时,接头的抗拉强度达到了121 MPa。

Control of Microstructure and Property of Pulse Laser Welded Joint of Magnesium/Titanium Alloy

The butt-joint laser welding of magnesium and titanium alloys is achieved by shifting laser pulses on the magnesium side and adding copper interlayers.The diffusion of elements and reaction characteristics at the interface are investigated.Furthermore,the effect of the thickness of the copper interlayer on the microstructure and mechanical properties of the joint is investigated.In addition,the primary causes of joint fractures are analyzed.The results show that the copper interlayer improves the microstructure at the weld/titanium interface and increases the content of Ti-Cu compounds near the interface.As the thickness of the copper interlayer increases,the thickness of the Ti2Cu reaction layer at the interface also gradually increases and becomes continuous.Moreover,the fracture position of the joint moves from the interface reaction layer to the weld zone.When the thickness of the copper interlayer reaches 30μm,the tensile strength of the joint reaches 121 MPa.