Room-temperature deformation behavior of Mo[sbnd]42Re alloy revealed by in-situ SEM-EBSD

Mo[sbnd]42Re alloy, with exceptional high-temperature strength and irradiation resistance, serves as a promising candidate for nuclear reactor cladding tubes and aerospace applications. In this study, the room-temperature deformation behavior of Mo-42 wt% Re alloy was systematically investigated using in-situ scanning electron microscopy coupled with electron backscatter diffraction (SEM-EBSD) during tensile testing. Research results demonstrated that the alloy exhibited exceptional ductility with high tensile strength and substantial plastic elongation, showing continuous strain hardening without premature failure. Comprehensive microstructural analysis revealed that deformation twinning on {112}⟨111⟩ systems dominated the plastic deformation process, while conventional dislocation slip remained limited despite favorable Schmid factors of 0.47–0.49 on activated {112}⟨111⟩ and {211}⟨111⟩ slip systems. EBSD mapping demonstrated progressive grain fragmentation through the formation of low-angle grain boundaries and twin-induced interfaces, with individual grains experiencing substantial lattice rotations averaging 24.9°. Multiple twin variants frequently activated within single grains, creating complex internal structures that contributed to effective strain accommodation and sustained work hardening. Kernel Average Misorientation analysis confirmed significant dislocation accumulation near twin boundaries and slip features, with local misorientation increasing from 0.129° to 0.521° throughout the deformation process. These findings demonstrate that rhenium addition fundamentally alters the deformation mechanisms in molybdenum by promoting twinning over slip, providing an alternative pathway for plastic deformation that maintains ductility at ambient temperatures where conventional slip systems are less active, offering new perspectives for the design of cladding tubes.