Amorphization, mechano-crystallization, and crystallization kinetics of mechanically alloyed AlFeCuZnTi high-entropy alloys

• Novel AlFeCuZnTi high-entropy alloys were prepared by high energy ball milling. • Amorphization and mechano-crystallization into BCC solid solution was observed in equiatomic alloy. • BCC solid solution was obtained for the non-equiatomic alloy during mechanical alloying. • Crystallization activation energy was correlated to the self-diffusion of the constituting elements. Equiatomic and non-equiatomic AlFeCuZnTi high-entropy alloys (HEAs) were prepared by high energy ball milling of elemental powders. For the equiatomic HEA with chemical composition at the boundary of solid solution and amorphous phase regions, an amorphous phase was obtained at moderate milling times, which was mechano-crystallized into a BCC solid solution by continued milling. For the non-equiatomic HEA with chemical composition well within the solid solution region, the same BCC solid solution was obtained during mechanical alloying. The crystallization kinetics of the amorphous HEA was studied by differential scanning calorimetry (DSC) thermal analysis. The crystallization activation energy (calculated based on the Kissinger equation) was correlated to the mean self-diffusion activation energy of the constituting elements, which was related to the multi-component nature of HEAs.