Effect mechanism of second phase particle types on high temperature compressive properties and thermal deformation behavior of Mo–Re alloy

Molybdenum-rhenium (Mo-Re) alloys are promising candidates for fuel cladding in advanced nuclear reactors owing to their attractive combination of neutronics and physical properties, including low neutron absorption and tailorable density. However, its insufficient high-temperature strength seriously restricts its long-term service as a reactor core in high temperature environment. In this study, the thermal compression properties of sintered bodies, which can strip away the interference from complex processing, were compared. The effects of different particles (ZrO 2 , ZrC, Ti 3 AlC 2 ) on the evolution law and deformation mechanism were clearly revealed. The results showed that the Mo-Re alloy doped with ZrO 2 , ZrC, and Ti 3 AlC 2 achieved compressive strengths of 209 MPa, 217 MPa, and 230 MPa at 1400 °C, which significantly exceeded the corresponding values for pure Mo-Re by 17.4%, 21.9%, and 29.2%. The Ti 3 AlC 2 phase had the best strengthening effect because of its unique layered structure, which could effectively anchor grain boundaries and hinder dislocation movement. The introduction of three types of second phase particles could all hinder the movement of dislocations in Mo-Re alloys and increase their dynamic recrystallization temperature, which provided a new research direction for designing low-rhenium molybdenum-based alloys for a high temperature environment.