Formation of Mg–Cu–Zn–Y bulk metallic glasses with compressive strength over gigapascal

The Mg55+xCu30−xZn5Y10 bulk metallic glasses (BMGs) with diameter of at least 3 mm were successfully fabricated in compositional range at x = 3–15 by conventional Cu-mold casting method. This kind of BMG alloys have supercooled liquid region (SLR) from 40 to 65 K, γ-value from 0.390 to 0.417, and the reduced glass transformation temperature from 0.543 to 0.576. By increasing the Zn content to 7%, the compressive strength of Mg-based BMG alloy reaches about 1.1 GPa. Vein pattern morphology has been observed in fractured surface of the Mg58Cu25Zn7Y10 alloy. The thermal, mechanical, and acoustic measurements indicate that Mg–Zn–Cu–Y BMGs are intrinsically brittle and are of good GFA. It is suggested that the correlation of elastic constants and mechanical properties of alloys could guide the Mg-based BMGs design.