Abstract:Mg₆₅Cu₂₅Y₁₀ bulk amorphous alloy specimens prepared by conventional copper mould method were heated at 200 °C for different time and the phase contents as well as microstructure were studied. The XRD results show that the crystallization of Mg₆₅Cu₂₅Y₁₀ bulk amorphous alloy specimen becomes complete as the treating time increases and Mg₂Cu, Mg₂₄Y₅ and HCP-Mg crystalline phases are found. Snowflake-like morphology is found in different specimens through SEM observation. The EDS patterns show that the composition of the snowflake-like structure is close to that of the as-cast alloy. Laminated structures are observed from the TEM images of the snowflake-like structure. From the electron diffraction patterns, it is seen that the snowflake-like structure is the combination of Mg₂₄Y₅ and amorphous matrix. The FCC-Mg phase in the matrix transforms into HCP-Mg during the heat-treating process.

Key words: Mg-based bulk amorphous alloy; crystallization; snowflake-like structure; laminated structure