Crystallization behavior of Mg–Cu–Y amorphous alloy

Abstract

Amorphous Mg61Cu24Y15 ribbons were manufactured by melt-spinning at wheel speeds in the range 5–20 ms−1. The crystallization behavior of amorphous ribbons was investigated by a combination of differential scanning calorimetry (DSC) and X-ray diffractometry. DSC measurements showed that the amorphous ribbons exhibit distinct glass transition temperature and wide supercooled liquid region before crystallization. During continuous heating three exothermic peaks and two endothermic peaks were observed. The characteristic thermodynamic parameters such as T g, T x , ΔT x , and T rg are around 432–439, 478–485, 46–54 K, and 0.55–0.56, respectively. Isothermal annealing DSC traces for this amorphous alloy, the first crystallization peak showed a clear incubation period and Avrami exponent was found to be 2.30–2.74, which indicate that the transformation reaction involved nucleation and three-dimensional diffusion controlled growth. Mechanical properties of the as-quenched and subsequently annealed ribbons were examined by Vickers microhardness (HV) measurements. Results showed that microhardness of the as-quenched ribbons were about 309 HV. However, the results also showed that microhardness of the rapidly solidified ribbons increases with the increasing temperature.