The fusion welding of molybdenum (Mo) and copper (Cu) is challenging task due to significant differences between chemical composition and physical properties of the two metals. A sound quality laser beam welding (LBW) joint between Mo and Cu is developed through the addition of pure Ni as an interlayer and laser beam offsetting. The evolution of microstructure in weld zone (WZ) and its impact on joint performance is analyzed through scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electron backscattered diffraction (EBSD), tensile and hardness test. At room temperature, the LBW joint between Mo and Cu is ruptured from heat affect zone (HAZ) near fusion zone (FZ) under a tensile load of 209 MPa. The addition of Ni as interlayer between LBW joint of Mo and Cu contributed an increase of 37.79% in tensile strength and the joint is ruptured from HAZ beside the base material Cu. Such improvement in joint performance is attributed to grain refinement in FZ, coarsening of transition zone (TZ) between Mo and Cu and directional solidification towards Cu rich region in FZ due to addition of Ni into LBW joint between Mo and Cu. The research results provide reference for the welding between dissimilar materials with significantly different melting points.

由于两种金属的化学成分和物理性能之间存在显着差异，钼 (Mo) 和铜 (Cu) 的熔焊是一项具有挑战性的任务。通过添加纯镍作为夹层和激光束偏移，开发了 Mo 和 Cu 之间的高质量激光束焊接 (LBW) 接头。通过扫描电子显微镜(SEM)、能谱仪(EDS)、电子背散射衍射(EBSD)、拉伸和硬度测试分析焊缝区(WZ)组织的演变及其对接头性能的影响。在室温下，Mo和Cu之间的LBW接头在209 MPa的拉伸载荷下从熔合区（FZ）附近的热影响区（HAZ）断裂。添加Ni作为Mo和Cu的LBW接头之间的夹层增加了37。抗拉强度为 79%，接头从母材 Cu 旁边的 HAZ 处断裂。接头性能的这种改善归因于 FZ 中的晶粒细化、Mo 和 Cu 之间的过渡区 (TZ) 的粗化以及由于将 Ni 添加到 Mo 和 Cu 之间的 LBW 接头而导致 FZ 中富铜区域的定向凝固。研究结果为熔点显着不同的异种材料之间的焊接提供参考。