Glass Forming Ability and Crystallization Kinetics of Cu-Zr-Al-(Y, Ag) Amorphous Alloy

Cu-Zr-Al-(Y, Ag) amorphous alloy ribbons of Cu50Zr42Al8, Cu46Zr47-xAl7Yx(x=2, 5), Cu43Zr42Al8Ag7, and Cu43Zr42Al8Ag5Y2 were prepared using the single roller melt-spinning method. The glass forming ability and non-isothermal crystallization behavior of the amorphous alloys were investigated by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) in a continuous heating mode. The experimental results show that the glass forming ability and thermal stability of Cu-Zr-Al amorphous alloys are improved by adding minor amounts of Y and Ag, and the effect of Ag on the glass forming ability is more significant than that of Y. Compared to the Cu50Zr42Al8 alloy, the width of the supercooled liquid region of the Cu46Zr47-xAl7Yx(x = 2 and 5) alloys increased by 19 K and 30 K, respectively. The reduced glass transition temperature (Trg) and the parameter γ of the two alloys enhanced separately. Compared to the Cu50Zr42Al8 alloy, the Trg and γ values of both Cu43Zr42Al8Ag7 and Cu43Zr42Al8Ag5Y2 alloys enhanced noticeably up to 0.619, 0.417, and 0.609, 0.412, respectively. The crystallization activation energies of the amorphous alloys calculated by the Kissinger and Flynn Wall Ozawa equations increased with the addition of minor Y and Ag into the Cu50Zr42Al8 alloy. The addition of Y and Ag significantly improved the thermal stability of the Cu50Zr42Al8 amorphous alloy.