Glass-forming ability and thermal stability of gas-atomized Zr50Cu40Al10 metallic glass powders

A Zr50Cu40Al10 (at.%) alloy was atomized by high pressure Ar gas, and the oxygen content, morphology, microstructure, phase composition, glass-forming ability and thermal stability of the as-atomized powders were investigated. Most of the powders are spherical in shape, but the surface morphologies are different for powders of different sizes. Powders with a size below 38 mu m show an amorphous characteristic. The presence of oxygen in the metallic glass powders leads to heterogeneous nucleation of crystalline phases, and the smallest powders have the highest cooling rate, so even with oxygen contamination, it is possible to prevent the crystallization process. Oxygen decreases the thermal stability and the glass-forming ability of the metallic glass powders compared with the Zr50Cu40Al10 bulk metallic glass. The metallic glass powders also show a high thermal stability indicated by T-rg, gamma, and delta parameters.