Influence of Mo content on the γ-phase stability and properties of U-Mo alloy

Abstract

U-Mo alloys have been considered as the potential new advanced nuclear fuel, due to its favourable irradiation stability associated with the presence of the metastable γ-phase in the microstructure. Thus its γ-phase stability and performance are of great importance. In this work, three kinds of U-Mo alloys with the content of 6, 8 and 10wt.% Mo were prepared by non consumable arc melting technology, the homogenization annealing and heat treatment of isothermal decomposition. Through metallographic microscope, scanning electron microscope (SEM), X-ray diffraction, Brinell hardness tester, the microstructure and mechanical properties of U-Mo alloys were investigated. The results indicate that the stability of γ-phase in the U-Mo alloy is directly related to the content of Mo. With the increase of Mo, the stability of γ-phase is enhanced and the decomposition of γ-phase is delayed during the isothermal decomposition at 565°C. In addition, the mechanical properties of this alloy are closely associated with its phase rather than directly related to the content of Mo.