Achieving an unprecedented strength-ductility balance of molybdenum alloy by homogeneously distributing yttrium-cerium oxide

Abstract

Rare earth (Y/Ce) were homogeneously distributed in molybdenum alloys by liquid-liquid doping and powder metallurgy method, and the molybdenum alloys plates were obtained after rolling. The results show the rare earth form nanoscale Y2O3 and CeO2 particles which were concomitant in molybdenum matrix. The rare earth oxides particles significantly refine microstructure and improve mechanical properties of the rolled molybdenum plate. The adding of 0.8%Y2O3 and 0.12%CeO2 made the micro fringe spacing in microstructure of rolled molybdenum alloy reduce 52.43%. The newly developed molybdenum alloys have an unprecedented strength-ductility balance compared with previous other molybdenum alloys. And high tensile strength and elongation were obtained simultaneously. The tensile strength of the rolled Mo-0.8%Y2O3-0.12%CeO2 alloy plate reaches 917 MPa with a 13.9% elongation, increased by 21.9% and 55.5% over a pure molybdenum plate, respectively. The strength-elongation product of the new molybdenum alloy annealed at 1200 ℃ could reach 2.4 times that of pure molybdenum. The addition of the nanoscale rare earth oxides to the Mo-alloy introduces Orowan strengthening and fine grain strengthening which changes fracture mode, resulting in excellent strength-ductility balance.