Glass-forming ability and mechanical properties of Cu₅₀ Zr_50-xTi_x alloys

Glass-forming ability (GFA) of Cu₅₀Zr_50-x Ti_x (x = 0-50 at.%) alloys was investigated by melt-spinning and copper mould casting methods. Bulk metallic glasses can be formed in the composition range of 0-15 and 35-45 at.% Ti. The x = 7.5 and 40 alloys show the best GFA in the local compositional vicinity, and critical diameters for glass formation is 5 and 3 mm, respectively. The GFA of the x = 20-30 alloys was degraded due to appearance of a Mg₂Zn-type Laves phase in the center portion of Cu-Zr-Ti diagram. The supercooled liquid temperature region and reduced glass transition temperature are 40 K, 0.587, respectively, for Cu₅₀ Zr_42.5Ti_7.5, and 44 K, 0.556, respectively, for Cu₅₀Zr₁₀Ti₄₀. These glassy alloys exhibit the high compressive fracture strength. The fracture strength and plastic strain before failure are 1798 MPa, 1.0%, respectively, for Cu₅₀Zr_42.5Ti_7.5, and 1810 MPa, 1.5%, respectively, for Cu₅₀Zr₁₀Ti₄₀.