Fabrication of Cu-Ti-Zr Based Amorphous Alloys by Mechanical Alloying

Cu₄₀Ti_60-xZr_x (x = 0,10,30,50) amorphous alloys were fabricated successfully by using mechanical alloying method. The mechanism of amorphization was discussed by investigating the transformation of Cu-Ti-Zr alloy powders from crystallization to amorphous state in the process of mechanical alloying. The thermal stability and crystalline phase of amorphous alloys were also investigated. It is shown that the amorphous is formed from the original elements directly, and no metallic compounds appear in the solid-state reaction. The amorphization mechanism may be explained by the vacancy diffusion model. The DSC traces of fully amorphous Cu₄₀Ti_xZr_y powders show that the onset crystallization temperature (T_x) is increased with the decrease of Ti content and the increase of Zr content. The Cu₄₀Ti₃₀Zr₃₀ and Cu₄₀Ti₁₀Zr₅₀ amorphous alloys were annealed near the onset crystallization temperature, T_x. It is found that Zr₂Cu, Cu₄Ti and a little unidentified crystal phases were precipitated in the Cu₄₀Ti₁₀Zr₅₀ amorphous alloy after annealed for 15 min, whereas there were no precipitates in the Cu₄₀Ti₃₀Zr₃₀ amorphous alloy.