Effect of Er doping on glass-forming ability of Co₅₀ Cr₁₅ Mo₁₄ C₁₅B₆ alloy

Bulk glass formation of the Co-Cr-Mo-C-B-Er alloy system was investigated in this paper. The Co₅₀ Cr₁₅ Mo₁₄ C₁₅ B₆ (at.%) alloy could be cast into fully glassy rod with a diameter up to 2 mm. By adding 2 at.% Er to this alloy, the critical diameter for glass formation reached 10 mm. The excellent glass formability of the Er-doped alloy was mainly attributed to its relatively large reduced glass transition temperature of 0.61, near-eutectic composition, and the necessity of redistribution of the Er atoms for precipitation of crystalline Co₆Mo₆C phase in the undercooled liquid on cooling.