冷热循环处理对铸态镁合金组织及力学性能的影响  

Effect of thermal-cold cycling treatment on microstructure and mechanical properties of as-cast magnesium alloys

作　　者：谢丽初[1,2] 姜勇[3] 蒋琼[2] 陈鼎[2] 

机构地区：[1]邵阳学院机械与能源工程系,湖南邵阳422000 [2]湖南大学材料科学与工程学院,湖南长沙410082 [3]上海航天精密机械研究所,上海201600

出　　处：《金属热处理》2012年第11期71-75,共5页Heat Treatment of Metals

基　　金：国家自然科学基金(50804015);教育部“新世纪优秀人才资助计划”(NCET-10-0360)

摘　　要：采用硬度检测、拉伸试验、TEM、SEM观察等方法对于两种经过冷热循环处理后的铸态镁合金AZ91和ZK60在力学性能及微观组织的变化进行了研究。研究结果表明:冷热循环处理比单独热处理或深冷处理能更有效提高合金力学性能,对于AZ91镁合金深冷处理24 h+T6效果最明显,对ZK60合金,深冷处理16 h+T6的循环处理则是最佳工艺。冷热循环处理后改变了AZ91合金中β-Mg17Al12相的数量和形貌,而在ZK60合金组织中则发现了细小的杆状相和碟状相析出。Effects of thermal-cold cycling treatment on microstructure and mechanical properties of AZ91 and ZK60 as-cast magnesium alloys were investigated by hardness test,tensile test and microstructure analysis.The results show that the mechanical properties of the samples treated by thermal-cold cycling treatment are higher than those of just T6 treated or deep cryogenic treated samples.The optimum heat treatment process are deep cryogentic treatment（24 h）＋T6 for AZ91 alloy and deep cryogentic treatment（16 h）＋T6 for ZK60 alloy,respectively.The improvement of mechanical properties of AZ91 alloy is contributed to that the number and shape of β-Mg17Al12 changed,while in ZK60 alloy,the increased density of rod-like and disc-shaped precipitates are the main reasons.

关 键 词：镁合金 AZ91 ZK60 冷热循环处理 力学性能 显微组织 

分 类 号：TG166.4[金属学及工艺—热处理]