LAUSR

Abstract The molybdenum alloys doped with different contents (0.3, 0.6, 0.9, 1.5 and 2.5 wt %) La 2 O 3 were prepared via solid-solid doping method followed by vacuum hot-pressing sintering. SEM observation and laser diffraction particle size analyzer demonstrated that the presence of La 2 O 3 particles could availably refine the Mo powders after high energy ball milling for 15 h. For the sinters, the grain size of Mo-La 2 O 3 alloys was greatly decreased and the minimum was 83% less compared with pure Mo. TEM analysis revealed that submicro- and nano-scale La 2 O 3 particles were distributed in Mo matrix. Especially, most of the nano-scale La 2 O 3 particles were located within the grains. Meanwhile, Mo-La 2 O 3 alloys with high relative density were obtained. The uniaxial compression tests results showed that the addition of La 2 O 3 particles also improved the yield strength of Mo alloys. Due to the optimized distribution of La 2 O 3 particles, a yield strength peak that is 78% higher compared with pure Mo is exhibited in Mo-0.9 wt % La 2 O 3 alloy. The quantitative relationships between the yield strength and the size, as well as the volume fraction of La 2 O 3 particles and Mo grain size were presented. Calculation results showed that refinement strengthening contributed more compared with Orowan strengthening.