Nanocrystallization of Cu–(Zr or Hf)–Ti metallic glasses

Crystallization of the Cu₆₀Zr₃₀Ti₁₀ and Cu₆₀Hf₂₅Ti₁₅ metallic glasses was studied by x-ray diffractometry, transmission electron microscopy, differential scanning and isothermal calorimetries. Metastable Cu–Zr–Ti and Cu–Hf–Ti cubic phases primarily precipitated in the Cu₆₀Zr₃₀Ti₁₀ and Cu₆₀Hf₂₅Ti₁₅ metallic glasses. The Cu₆₀Zr₃₀Ti₁₀metallic glass crystallizes with low energy barrier for nucleation while crystallization of the Cu₆₀Hf₂₅Ti₁₅ metallic glass takes place by nucleation and diffusion-controlled growth of cubic Cu–Hf–Ti phase particles with constant nucleation rate. The Cu₆₀Hf₂₅Ti₁₅ metallic glass is characterized by a low activation energy for nucleation.