Relating melting temperature with structure heterogeneity and plasticity of Zr57Cu20Al10Ni8Ag5 bulk metallic glass

Abstract

In the present paper, a series of Zr57Cu20Al10Ni8Ag5 BMGs are prepared by controlling the melting temperature. Glass forming ability and thermal-stability of Zr57Cu20Al10Ni8Ag5 BMGs increases continuously with the melt temperature moves to higher overheating state. However, the compressive plasticity decreases from 16.3% for the BMG with the lowest melting temperature of 1273K to 0% for the BMG with the highest melting temperature of 1573K. By structure characterization using HRTEM, the results show that nanocrystals and local segregation of atom clusters exist in the glassy matrix of the BMGs with lower melting temperature. Difference in plastic performance is considered relating with the heterogeneous structure caused by the different amount and distribution of nanocrystals and clusters. The reason for the plastic performance with respect to different melting temperature is also discussed from the aspect of cooling rate, amount of free volume, and oxygen content.