TENSILE BEHAVIOR AND MICROSTRUCTURE OF NEUTRON-IRRADIATED MO-5-PERCENT RE ALLOY

This work reports the effect of heat treatment on the tensile behavior and microstructure of neutron-irradiated Mo-5% Re alloy. Stress-relie ved and recrystallized specimens conditions were irradiated at five te mperatures between 646 and 1073 K in FFTF/MOTA. The exposure levels we re in the range of 6.8 to 34 dpa depending on the irradiation temperat ures. 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 spec imens irradiated at 873 and 1073 K ranged from 5 to 10%, and that of r ecrystallized specimens irradiated at 1073 K was 5%. The fracture mode s of these specimens were transgranular type. Voids were observed in a ll of the irradiated specimens, but precipitates were found only in sp ecimens 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 allo y showed the ductility after neutron exposures of relatively high flue nces.