Effects of Additional Hf on the Thermal Stability and Mechanical Properties of Cu-Zr-Ag Bulk Glassy Alloys

Abstract

The thermal stability, crystallization behavior and mechanical properties of the Cu₄₅Zr_45−xHf_xAg₁₀ (x=0 to 45 at%) glassy alloys have been investigated. The glass transition temperature (T_g), crystallization temperature (T_x), liquidus temperature (T_l) and the supercooled liquid region ΔT_x (=T_x−T_g) increase with increasing Hf content. The reduced glass transition temperature (T_g⁄T_l) values are in the range from 0.54 to 0.59. The Vicker’s hardness (H_V), Young’s modulus (E) and compressive fracture strength (σ_c,f) of the Cu₄₅Zr_45−xHf_xAg₁₀ (x=0 to 25 at%) bulk glassy alloys increase linearly with increasing Hf content and reach the maximum values of 554, 123 GPa and 2020 MPa, respectively, for Cu₄₅Zr₂₀Hf₂₅Ag₁₀ alloy. A different crystallization behavior is observed for Cu₄₅Zr₄₅Ag₁₀ and Cu₄₅Hf₄₅Ag₁₀ glassy alloys.