Crystallization microstructure of Mg65Cu25Y10 bulk amorphous alloy
(School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China)
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