Effect of rare earth oxide doping on microstructure and mechanical property of Mo-30 W solid solution alloy

Oxide dispersion-strengthened (ODS) molybdenum‑tungsten (Mo W) alloys are ideal materials for plasma-facing components of fusion reactors. In this paper, the effects of rare earth oxides (RE x O y ) Y 2 O 3 , CeO 2 and La 2 O 3 on the sintering behavior , microstructural and mechanical properties of Mo W solid solution alloys were investigated. The initial alloy powders were produced by spray drying combined with the two-step reduction method (composed of carbothermal reduction and deep hydrogen reduction steps), and the solid solution alloy with good mechanical properties was prepared by subsequent sintering. The results showed that the doping of rare earth oxides suppressed the grain growth of Mo W alloy, and thus improved the mechanical properties. Compared with CeO 2 and Y 2 O 3 , the doping of La 2 O 3 is more favorable to obtain dense and fine-grained Mo W solid-solution alloys. The doping of La 2 O 3 produced a larger Zener force and interfacial drag force, which effectively hindered the grain boundary migration and refined the grains. The microhardness and bending strength of Mo-30 W-1La 2 O 3 alloy reached the maximum values of 557 HV and 771 MPa.