Avrami exponent and isothermal crystallization of Zr/Ti-based bulk metallic glasses

The isothermal crystallization kinetics of Zr/Ti-based bulk metallic glasses (BMGs) have been investigated by using Avrami exponent. It is a constant nucleation rate and a constant number of quenched-in nuclei that cause the linear John–Mehl–Avrami (JMA) modes in Avrami exponents of Zr62Al8Ni13Cu17 and Zr65Al8Ni10Cu17 BMGs, respectively. However, sub-Tg pre-annealing of Zr62Al8Ni13Cu17, and multiple-step phase transition in Ti43Cu43Zr7Ni7 and Ti45Zr5Cu40Ni7.5Sn2.5 make their Avrami exponents deviate from the linear JMA mode. The difference in Avrami exponents maybe provides useful information for performing the microstructure control of BMG composites upon isothermal annealing.