The influence of rare earth on Co-based alloy

The observation and analyses have been made on Co-based alloys using various methods in the paper. The results show that trace rare-earth elements can increase tensile strength of metallic cobalt, reduce porosity slightly, and the distribution of pores become dispersed and homogeneous. Rare-earth phase distributes mainly in the pores, grain boundary and phase boundary of alloys, and a small amount in the Co phase. The shape is normally round, and below 0.5 micron in size. The composition is Y2WO6 compound and Co2Y intermetallic compound. The addition of rare-earth enhances stacking fault energy of Co phase. Width of stacking fault decreases obviously. The bias precipitation of rare-earth in the grain boundary and phase boundary results in a smaller and homogenized alloy construction.