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

Abstract

A new Cu-based bulk glassy alloy with high tensile fracture strength above 2000 MPa was formed in a (Cu_0.6Zr_0.3Ti_0.1)₉₈Y₂ alloy by copper mold casting. The maximum sample thickness for glass formation is 4 mm for Cu₆₀Zr₃₀Ti₁₀ and increases to 5 mm for the 2%Y-containing alloy. The addition of 2%Y also causes an increase in the supercooled liquid region (ΔT_x=T_x−T_g) from 36 to 50 K and in the reduced glass transition temperature (T_g⁄T_l) from 0.62 to 0.63. The increase in the glass-forming ability (GFA) is presumably due to the increase in ΔT_x and T_g⁄T_l. The bulk glassy (Cu_0.6Zr_0.3Ti_0.1)₉₈Y₂ alloy exhibits good mechanical properties, i.e., 1780 MPa for yield strength, 2030 MPa for tensile fracture strength, 2100 MPa for compressive fracture strength, 1.7% for elastic elongation and 1.5% for plastic elongation. The distinct plastic elongation indicates good ductile nature of the Cu-based bulk glassy alloy. The success of synthesizing the new Cu-based bulk glassy alloy with high GFA and good mechanical properties allows us to expect the extension of application fields as a new engineering material.