Effects of partial replacement of Cu and Y by Bin Mg–Cu–Y amorphous alloys

The effects of replacing Cu or Y by a small-sized B in the Mg65Cu25Y10 based alloy are examined. It is found that the replacement of Y by B consistently leads to apparent degradation in GFA; the large sized Y seems to be irreplaceable. In contrast, the replacement of the small sized Cu by the even smaller B to a small amount (1–5%) appears to be beneficial in terms of wider ΔT, higher GFA, thermal stability, and hardness, as well as lower density. In this study, the optimum quaternary alloy composition is identified to be Mg65Cu22Y10B3.