钛合金与钢焊接易生成金属间化合物, 对焊缝性能有显著影响。为探索钛合金与钢激光焊接的可行性, 对钛合金与合金钢进行了激光焊接工艺实验, 对比了钛合金与合金钢激光对焊、激光搭接焊及激光搭接熔钎焊三种工艺。利用金相显微镜、扫描电镜、能谱及 XRD对焊缝微观结构、断口形貌及元素成分进行了分析。结果显示, 钛合金与合金钢激光对焊与搭接焊熔池中元素扩散充分, 生成脆性金属间化合物, 使焊缝塑性降低甚至开裂。激光搭接熔钎焊方法通过优化焊接过程热输入, 可以控制熔池大小, 减缓元素扩散, 抑制金属间化合物的形成, 将金属间化合物的分布控制在有限区域内, 有助于提高钛合金与钢的焊接质量。

It is difficult to join titanium alloy and steel due to the formation of intermetallic compounds. In order to investigate thefeasibility of laser welding of titanium alloy and steel, laser butt welding, laser lap welding and laser lap brazing experiments wereconducted on a Nd: YAG laser materials processing system with five-axis CNC working station. Microstructure, chemical compositionof the joint were evaluated by optical microscopy, scanning electron microscopy equipped with energy dispersive spectrometer and X-ray diffractometer. The results show that laser butt welding and laser lap welding were unacceptable for joining titanium alloy andalloy steel because of the formation of intermetallic compounds. It is indicated that the size of the molten pool at the interface couldbe controlled by optimizing heat input during laser overlap brazing, so as to reduce the diffusion of Ti and Fe elements at theinterface, suppress the formation of Ti/Fe intermetallic compounds and increase the strength of the joint.