Bulk glass formation and mechanical properties for Cu–Hf–Ti–M (M = B,Y) alloys

The glass forming ability (GFA), nanohardness Hn and Young’s modulus E of ternary alloys in the compositional series Cu60Hf40−xTix (x = 5–35) are reported and discussed. Bulk glass formation was observed for the three alloys x = 17.5, 20 and 22.5, with critical rod diameters dc for a fully glassy structure of 4, 4 and 3 mm, respectively. A dc of 4 mm was also observed for the Cu55Hf25Ti20 alloy. These compositions generally had the highest values of reduced glass temperature while no correlation was observed between the GFA and the parameter ΔTx. Both Hn and E surprisingly showed minima at ∼20 at.%Ti for the Cu60Hf40−xTix series. The addition of 1 at.%B or Y to the Cu60Hf22.5Ti17.5 alloy slightly decreased the GFA but slightly increased the elastic modulus.