均匀化对AZ80-2.0Ca合金微观组织和硬度的影响  

Effect of Homogenizing Heat Treatment on Microstructure and Hardness of AZ80-2.0Ca Magnesium Alloy

作　　者：王忠军[1] 徐阳[1] 朱晶[1] 李胜利[1] 

机构地区：[1]辽宁科技大学材料与冶金学院

出　　处：《特种铸造及有色合金》2012年第6期500-504,共5页Special Casting & Nonferrous Alloys

基　　金：辽宁省教育厅材料成型与组织性能控制重点实验室开放基金资助项目(201113);鞍山市科技局项目(2011MS05)

摘　　要：采用DSC热分析仪、金相显微镜、扫描电镜和显微硬度计等研究了AZ80-2.0Ca铸造镁合金的微观组织,分析了均匀化热处理后合金的微观组织演变和显微硬度的变化规律。结果表明,该合金由基体α-Mg相,β-Mg17Al12相和(Mg,Al)2Ca相组成;Ca元素的加入使β-Mg17Al12相的熔点由437℃提高到457℃;在430℃下保温2h时β-Mg17Al12相完全溶解,继续延长保温时间至24h时,(Mg,Al)2Ca相未见溶解;当合金在515℃保温0.5h时,β-Mg17Al12相完全溶解,继续延长保温时间至4h时,(Mg,Al)2Ca相开始分解并转变为Al2Ca和Mg;合金共晶相分解后,其硬度开始下降,分解完成后其硬度趋于稳定,且515℃均匀化热处理后的合金硬度小于430℃均匀化热处理后的合金硬度。The microstructures of as-cast AZ80-2.0Ca magnesium alloy were investigated,and effects of homogenizing treatment on microstructure evolution and hardness change of the alloy were analyzed by DSC thermal analyzer,optical microscope（OM）,scanning electron microscopy（SEM） and micro-hardness tester.The results show that the as-cast AZ80-2.0Ca magnesium alloy is mainly composed of α-Mg phase,β-（Mg17Al12） phase and（Mg,Al）2Ca phase.The melting point of β-（Mg17Al12） phase in the alloy is increased from 437 ℃ to 457 ℃ with Ca addition.The β-（Mg17Al12） phase is completely dissolved at 430 ℃ for 2 h,however,the（Mg,Al）2Ca phase is not dissolved at 430 ℃ for 24 h.In addition,the β-（Mg17Al12） phase is completely dissolved at 515 ℃ for 0.5 h,and the（Mg,Al）2Ca phase is decomposed and transformed into Al2Ca phase and Mg at 515 ℃ for 4 h,and then the Mg atoms are diffused into the matrix.However,the Al2Ca phase is not dissolved even though for 24 h.Micro-hardness of the alloy is decreased with the solution of the β-（Mg17Al12） phase and（Mg,Al）2Ca phase and it tends to be constant after decomposition completion.However,the micro-hardness of the AZ80-2.0Ca magnesium alloy after homogenization treatment at 515℃ is lower than that at 430 ℃.

关 键 词：AZ80-2.0Ca合金 均匀化 微观组织 硬度 

分 类 号：TG146.22[一般工业技术—材料科学与工程]