Weldability of Molybdenum–Rhenium Alloy Based on a Single-Mode Fiber Laser

Due to its high thermal conductivity and favorable machinability, molybdenum–rhenium (Mo–Re) alloys have huge prospects in the field of high-temperature heat pipes. However, the weldability of Mo–Re alloys has not yet been systematically investigated. Based on an orthogonal test, the influence law of the single-mode fiber laser welding parameters on the weld profile and the mechanical properties of the joints was studied. Furthermore, the existence mode and the distribution law of Re in the fusion zone (FZ) were explored using X-ray photoelectron spectrometer (XPS) and the electron backscattered diffraction (EBSD) system. The results showed that weld penetration and width are most significantly influenced by power, and that these increased with increasing power. The tensile strength of the Mo–Re alloy joints reached 250 MPa, and no obvious hardening was found in the FZ. Re in the FZ also appeared as ReO2, ReO3, and ReC, apart from the atomic state.