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 (T_g), crystallization temperature (T_x), the temperature interval of the supercooled liquid region (ΔT_x=T_x−T_g) and the melting temperature (T_m) 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 T_m and an increase in the reduced glass transition temperature (T_g⁄T_m), 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.