Effects of additional Ag on the thermal stability and glass-forming ability of Cu–Zr binary glassy alloys

Thermal stability and glass-forming ability (GFA) of (Cu0.5Zr0.5)100−xAgx (x = 0–16) glassy alloys have been studied. Both of the supercooled liquid region (ΔTx) and the GFA greatly increase with increasing Ag content. The largest ΔTx of 80 K and the critical diameter (dc) of 6.0 mm were obtained for x = 12 and 10 alloys, respectively, and then decrease with further increasing Ag content. The substitution of Hf for Zr in Cu45Zr45Ag10 glassy alloy increases the stability of supercooled liquid and fracture strength, though the GFA decreases. The substitution of Al for Ag in Cu45Zr45Ag10 alloy is effective for the increase in ΔTx as well as GFA. The largest ΔTx of 86 K and dc of 9.0 mm were obtained for Cu45Zr45Al5Ag5 alloy. The GFA of the Cu–Zr-based alloys has better correlation with reduced glass transition temperature and γ value. The new bulk glassy alloys exhibit high fracture strength of 1774–2000 MPa with distinct plastic strains of 0.002–0.014.