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

The supercooled liquid region ΔTx of a Cu55Zr40Al5 (numbers indicate at.%) glassy alloy increased by the addition of noble metals (Ag, Pd or Au) and the largest ΔTx reached 87 K for Cu50Zr40Al5Pd5. The reduced glass transition temperature (Tg/Tl, where Tg is the glass transition temperature and Tl is the liquidus temperature) of Cu50Zr40Al5M5 (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, Youngʹs modulus, compressive fracture strength and plastic strain are 573–594, 106–118 GPa, 2050–2230 MPa and 0.004–0.015, respectively, for the Cu50Zr40Al5M5 (M = Ag, Pd, Au) bulk glassy alloys. The addition of noble metals to the Cu55Zr40Al5 glassy alloy is effective for improving the corrosion resistance in 1N H2SO4 solution. A different crystallization behavior was observed for Cu55Zr40Al5 and Cu50Zr40Al5Pd5 glassy alloys.