Effect of additional elements on the thermal stability of the Cu-Zr glassy alloys

The Cu-Zr binary alloys are known to have a high glass forming ability. Inoue et al. reported that the melt-spun Cu_xZr_100-x (x=25-75 at%) binary alloys could possess a single amorphous phase with a wide super-cooled liquid region. In this work, we focused on the Cu ₆₀Zr₄₀ glassy alloy with an extremely wide super-cooled liquid region, Δ T_x of about 75 K and replaced a part of the alloy with additional elements. We prepared the (Cu_0.6Zr _0.4)₉₇M₃ (M = B, Al, Si, Cr, Fe, Co, Ni, Pd, Ag, Au ), (Cu_0.6Zr_0.4)₉₄M₆ (M = B, Al, Si, Cr, Fe, Co, Ni, Ag) and the Cu₆₀Zr₃₅M₅ (M= B, Al, Si, Cr, Co, Ni, Zn) glassy alloys by the melt-spinning technique and investigated the thermal stability and the mechanical properties of those ternary alloys. It is found that addition of those elements causes a decrease in Δ T_x and that addition of Al, Si, Cr, or Ni increases the Vickers hardness of the alloy. The glass transition was not observed for the Cu₆₅Zr₃₅Si₅ alloy.