Effects of additional noble elements on the thermal stability and mechanical properties of Cu–Zr–Al bulk glassy alloys

Abstract

The supercooled liquid region Δ T x of a Cu 55Zr 40Al 5 (numbers indicate at.%) glassy alloy increased by the addition of noble metals (Ag, Pd or Au) and the largest Δ T x reached 87 K for Cu 50Zr 40Al 5Pd 5. The reduced glass transition temperature ( T g/ T l, where T g is the glass transition temperature and T l is the liquidus temperature) of Cu 50Zr 40Al 5M 5 (M = Ag, Pd or Au) glassy alloys is in the range from 0.60 to 0.61. The selection of the quaternary compositions enabled us to form bulk glassy alloys with diameters up to 3 mm. The Vickers hardness, Young's modulus, compressive fracture strength and plastic strain are 573–594, 106–118 GPa, 2050–2230 MPa and 0.004–0.015, respectively, for the Cu 50Zr 40Al 5M 5 (M = Ag, Pd, Au) bulk glassy alloys. The addition of noble metals to the Cu 55Zr 40Al 5 glassy alloy is effective for improving the corrosion resistance in 1N H 2SO 4 solution. A different crystallization behavior was observed for Cu 55Zr 40Al 5 and Cu 50Zr 40Al 5Pd 5 glassy alloys.