Tensile behavior and microstructure of neutron-irradiated Mo-5% Re alloy

Abstract

This work reports the effect of heat treatment on the tensile behavior and and microstructure of neutron-irradiated Mo-5% Re alloy. Stress-relived and recrystallized specimens conditions were irradiated at five temperatures between 646 and 1073 K in FFTF/MOTA. The exposure levels were in the range of 6.8 to 34 dpa depending on the irradiation temperatures. Tensile tests were carried out at room temperature and 673 K and microstructures of the irradiated specimens were observed by TEM. The Mo-5% Re alloy irradiated at high temperatures shows ductile behavior even at room temperature. The total elongation of stress-relived specimens irradiated at 873 and 1073 K ranged from 5 to 10%, and that of recrystallized specimens irradiated at 1073 K was 5%. The fracture modes of these specimens were transgranular type. Voids were observed in all of the irradiated specimens, but precipitates were found only in specimens irradiated above 792 K. It is important for the Mo Re alloy to be used in high-heat flux components of fusion reactors that the alloy showed the ductility after neutron exposures of relatively high fluences.