The effect of Ni substitution on the glass-forming ability and mechanical properties of Mg-Cu-Gd metallic glass alloys

The effect of substitution of Ni for Cu on the glass forming ability and mechanical properties was studied in Mg65Cu25−xNixGd10 (x = 0, 5, 10, 15, 20, 25) alloys by thermal analysis and X-ray diffractometry (XRD). With increasing x from 0 to 25 at.%, the glass transition temperature, Tg, of Mg65Cu25−xNixGd10 alloys increases from 417 to 450 K, and the onset temperature of crystallization, Tx, decreases slightly, resulting in a decrease in the supercooled liquid region. However, an appropriate substition of Cu by Ni (5 at.%) in Mg65Cu25Gd10 significantly improves mechanical properties, especially improves the ductility of Mg-based bulk metallic glass (BMG) while keeping good glass forming ability (GFA). The Mg65Cu20Ni5Gd10 BMG sample of 5 mm in diameter is fabricated by the conventional Cu-mold casting method in an argon atomsphere.