Composition dependence of crystal growth and its time evolution in supercooled liquid of Zr–Al–Cu glassy metals

Crystal nucleation and its time evolution during isothermal annealing in supercooled liquid of glassy metals Zr65Al10Cu25 ribbon, Zr50Al10Cu40 ribbon, and Zr50Al10Cu40 bulk are examined using a technique of differential thermal analysis. Time dependence of the fraction of crystallization in supercooled liquid at several temperatures is analyzed by the Johnson–Mehl–Avrami (JMA) formula. The Avrami exponents are 3.0±0.2 for Zr65Al10Cu25 ribbon, and 3.9±0.4 for Zr50Al10Cu40 ribbon and Zr50Al10Cu40 bulk. Relation between grown crystals in the supercooled liquid and the Avrami exponent can be explained reasonably. Plots of the fraction of crystallized volume versus a scaled time normalized by the half time of full crystallization almost collapse on a single curve. This suggests that the crystal growth obeys a universal process. The temperature dependence of the half time is discussed using the Williams–Landel–Ferry function.