Crystallization behavior of the Zr61Al7.5Cu17.5Ni10Si4 amorphous alloy

The ribbons of amorphous Zr61Al7.5Cu17.5Ni10Si4 alloy were studied by means of differential scanning calorimetry (DSC), X-ray diffractometry (XRD), high-temperature optical microscope and transmission electron microscopy (TEM). The activation energy for such the crystallization of the amorphous phase was about 360 and 370 kJ mole−1 calculated by Kissinger and Avrami plots, respectively. Kinetics for the crystallization was analyzed by means of Johnson–Mehl–Avrami equation and discussed regarding to the value of Avrami exponent. The average value of the Avrami exponent n was measured about 2.43 at the range from 698 to 713 K. In addition, the cube of crystal size as a function of isothermally annealing time presents a linear relationship for the Zr61Al7.5Cu17.5Ni10Si4 alloy. When the Zr61Al7.5Cu17.5Ni10Si4 alloy was isothermally annealed at 698 K, a Zr2Cu crystal with an average size of 105 nm was first observed at the early stage (30% crystallization) of crystallization. In addition, both nano-crystals of ordered fcc ZrCu (∼100 nm) and ordered fcc Zr3Al (∼30 nm) were observed to precipitate from the amorphous matrix upon the middle stage (50% crystallization) of crystallization.