Effect of Y₂O₃–CeO₂ two-phase dispersion strengthening on the grain size and tensile properties of Mo alloys

Mo–Y–Ce alloys doped by yttrium oxide (Y₂O₃) and cerium oxide (CeO₂) in different mass fraction were prepared by the nanometer spray doping technology and the powder metallurgy method. The two-phase dispersion strengthening effect of Y₂O₃ and CeO₂ on the grain size and mechanical properties of Mo alloys at room temperature was studied. The results show that Y₂O₃ restrains the abnormal growth of the individual grains and has the effect of precipitation strengthening. The mechanical properties of the Mo–Y alloy wires are closely related to the doping amount of Y₂O₃. When the mass fraction of Y₂O₃ is 0.60%, the tensile strength and yield strength of the ϕ1.8-mm Mo–Y alloy wires reach 1050 and 923 MPa, respectively. Because of the semi-coherent relationship between CeO₂ and the Mo matrix, CeO₂ has the good toughening effect. When the mass fraction of CeO₂ is 0.06%~0.08%, the grain size of the sintered Mo–Y–Ce alloys is smaller than 10 μm, the tensile strength and yield strength of the ϕ1.8-mm Mo–Y–Ce alloy wires are 1130 and 1018 MPa, respectively, the elongation reaches 28.5%. The tensile strength of ϕ0.18-mm Mo–Y–Ce alloy wires reaches 2510 MPa. The optimal composition of the Mo–Y–Ce two-phase dispersion strengthening Mo alloys is Mo–0.6Y₂O₃–(0.06~0.08)CeO₂.