Thermal stability and mechanical properties of Mg-Y-Cu-M (M = Ag, Pd) bulk amorphous alloys

Abstract

Magnesium-based bulk amorphous alloys with a diameter of 7 mm for Mg65Y10Cu15Ag5Pd5 were produced by a metallic mold casting method. The glass transition temperature (Tg), crystallization temperature (Tx), the temperature interval of the supercooled liquid region (ΔTx = Tx - Tg) and the melting temperature (Tm) are measured to be 437, 472, 35 and 707 K, respectively, for the Mg65Y10Cu15Ag5Pd5 alloy. The simultaneous addition of Ag and Pd to Mg-Y-Cu system causes a steep decrease in Tm and an increase in the reduced glass transition temperature (Tg/Tm), leading to an increase in the glass-forming ability. The Mg-Y-Cu-(Ag,Pd) bulk amorphous alloys have a high compressive fracture strength of 770 MPa. The simultaneous addition of Ag and Pd is useful for the improvements of glass-forming ability and fracture strength.