Synthesis and Thermal Stability of New Ni-Based Bulk Glassy Alloy with Excellent Mechanical Properties

Abstract

The thermal stability, glass-forming ability (GFA) and mechanical properties of the Ni-Ta-Ti and Ni-Ta-Ti-Zr glassy alloys have been investigated. As the Ti content increases, the supercooled liquid region ΔT_x(=T_x−T_g) and reduced glass transition temperature (T_g⁄T_l) of Ni₆₀Ta_40−xTi_x glassy alloys increase, showing maximum values of 63 K at 20%Ti and 0.59 at 25 at%Ti, respectively, and then gradually decrease. The addition of Zr to Ni-Ta-Ti alloys is effective for the increase in ΔT_x and T_g⁄T_l. The maximum ΔT_x and T_g⁄T_l values of 73 K and 0.60, respectively, are obtained for Ni₆₀Ta₁₅Ti₂₀Zr₅ alloy. The Ni-Ta-Ti-Zr glassy alloys were formed in the rod form with diameters of over 1.0 mm by copper mold casting. The Ni-Ta-Ti-Zr bulk glassy alloys exhibit excellent mechanical properties, i.e., the compressive fracture strength (σ_c,f) of 3180–3220 MPa and the compressive plastic elongation (ε_c,p) of 0.2–0.4%.