Mg65Cu25Y10块体非晶合金的晶化组织

摘要

将普通铜模浇铸法制得的Mg65Cu25Y10块体非晶合金试样置于200℃进行保温处理,对处理后的试样的相组成和显微组织进行研究.XRD分析结果表明,该块体非晶的晶化随保温时间的延长趋于完全,在此过程中有Mg2Cu、Mg24Y5和HCP-Mg等晶体相析出.通过SEM观察到雪花状组织,EDS结果表明该雪花状组织的成分接近于铸态合金的成分,TEM分析表明其为层片状结构.电子衍射花样分析表明,雪花状组织由Mg24Y5晶体和非晶相组成.在保温过程中,基体中的FCC-Mg会转变为HCP-Mg.%Mg65Cu25Y10 bulk amorphous alloy specimens prepared by conventional copper mould method were heated at 200 ℃ 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.