Low-energy ball milling technique was successfully used to synthesis new glassy Zr52Al6Ni8Cu14W20 multicomponent alloy powders using mechanical alloying method. During the intermediate stage of milling the atoms of Zr, Al, Ni, and Cu migrated and diffused into the W lattice to form a body-centered cubic solid solution phase. As the milling time increases, the obtained metastable powders are subsequently subjected to continuous defects and lattice imperfections that lead to a gradual change in the free energy so that solid solution phase transformed to another metastable phase (glassy). The glassy powders that were obtained after 720 ks milling are fully amorphous and have spherical-like morphology with an average particle size of 0.60 μm in diameter. The synthetic glassy Zr52Al6Ni8Cu14W20 alloy powder, which exhibits a glass transition temperature of 811 K, crystallizes at a high temperature (884 K) through a single sharp exothermic peak with an enthalpy change of crystallization of −5.48 kJ/mol. Whereas the supercooled liquid region before crystallization of the obtained glassy powders is 73 K, the reduced glass transition temperature (ratio between Tg and liquidus temperatures) was found to be 0.46. The fabricated glassy powders were consequently hot-pressed into bulk samples in an argon gas atmosphere at several temperatures with a pressure of 936 MPa. The samples that were consolidated within the temperature of the supercooled liquid region are fully dense, with relative density above ∼99.82%, and maintain their original homogeneous glassy structure. They have high Vickers microhardness values in the range between 8.46 and 8.62 GPa. They also show very high fracture strength (2.13 GPa) with an extraordinary high Young's modulus of 138 GPa. Neither yielding stress, nor plastic strain could be detected for this glassy alloy, the elastic strain of which is 1.47%.
Zr–Al–Ni Amorphous Alloys with High Glass Transition Temperature and Significant Supercooled Liquid Region