Thermal and Mechanical Properties of Cu-Based Cu-Zr-Ti Bulk Glassy Alloys

Abstract

New Cu-based bulk glassy alloys of Cu–Zr–Ti system were formed by copper mold casting. The maximum diameter is 4 mm for the Cu₆₀Zr₃₀Ti₁₀ alloy. The addition of Ti to Cu₆₀Zr₄₀ resulted in an increase in the glass-forming ability (GFA). As the Ti content increases, the glass transition temperature (T_g), crystallization temperature (T_x) and temperature interval of supercooled liquid region ΔT_x(=T_x−T_g) decrease, while the liquidus temperature (T_l) has a minimum of 1127 K around 20%Ti, leading to a maximum T_g⁄T_l of 0.63 in the vicinity of 20 at%Ti. The high GFA of the Cu-based alloys was obtained at the compositions with high T_g⁄T_l. The bulk glassy Cu₆₀Zr₃₀Ti₁₀ alloy exhibits Vickers hardness of 660, Young’s modulus of 114 GPa, fracture strength of 2150 MPa and compressive plastic elongation of 1.7%. The finding of the Cu-based bulk glassy alloy with high T_g⁄T_l above 0.60, high fracture strength above 2000 MPa and distinct plastic elongation is encouraging for future development as a new type of bulk glassy alloys which can be used for structural materials.