Tensile creep deformation behavior of Mo-14 %Re alloy at elevated temperature

Abstract

The creep properties of Molybdenum-14 %Rhenium alloy (MR14) were systematically investigated under temperatures ranging from 900 to 1200 °C and applied stresses of 100–150 MPa. Experimental results indicate that steady-state creep rate of MR14 alloy is as low as 7.5 × 10⁻⁷ at 1100 °C and 150 MPa. Compared with other high-temperature alloys under the same or similar temperature and stress conditions, this alloy demonstrates superior creep resistance. At 1100 °C, the corresponding stress exponent is 3.7, suggesting that the dominant creep mechanism is dislocation creep. At 150 MPa, the creep activation energy is 115.8 kJ/mol, which is lower than that of pure molybdenum for dislocation creep (approximately 240 kJ/mol). This characteristic can primarily be attributed to the rhenium effect, dislocation pipe diffusion, and the effective transmission of dislocations facilitated by abundant substructures. The fine grains formed through recrystallization exhibit heterogeneous distribution, effectively suppressing creep deformation and grain boundary sliding. Creep failure mainly originates from the nucleation, growth, and coalescence of creep voids.