Solid plasticity and supercooled-liquid thermoplasticity of Zr-Cu-enriched hypoeutectic Zr-Cu-Ni-Al cast glassy alloys

The plasticity of Zr-Cu enriched hypoeutectic Zr-Cu-Ni-Al cast glassy alloys (CGAs) was investigated to determine their tensile elongation as a solid at room temperature, and their precise thermoplastic moldability in a supercooled liquid state. The viscosity of the supercooled liquids was measured by using a penetration viscometer at a high-speed heating rate of 400 K/min. The results obtained show that with an increase in the Zr content, the glass transition temperature (Tg) tends to decrease, whereas the crystallization temperature (Tx) tends to increase. We observed tensile elongation with plural sliding shear bands in the Zr-Cu enriched Zr65Cu20Ni5Al10 CGAs at room temperature. Furthermore, the hypoeutectic Zr65Cu18Ni7Al10 CGA exhibits the widest ΔTx (=Tx−Tg) of about 170 K, with a low viscosity in the order of 105 Pa s being observed in the supercooled liquid under a heating rate of 400 K/min. The potential for printing micro-patterns on the surface of a glassy Zr65Cu18Ni7Al10 alloy is demonstrated by means of tough nanocrystalline Ni-W electro-plating molds.