铸造Mg-5Zn-0.6Zr-1RE-2Y镁合金的低温时效硬化及组织  

Microstructure and age-hardening of as-cast Mg-5Zn-0. 6Zr-1RE-2Y magnesium alloy aged at low temperature

作　　者：陈敬区[1] 刘江文[1] 焦东玲[1] 罗承萍[1] 

机构地区：[1]华南理工大学材料科学与工程学院,广东广州510640

出　　处：《材料热处理学报》2010年第12期112-117,共6页Transactions of Materials and Heat Treatment

基　　金：广东省自然科学基金资助项目(07006483)

摘　　要：对铸造Mg-5Zn-0.6Zr-1RE-2Y镁合金进行450℃固溶+100℃时效处理,时效时间0～5个月,并通过显微硬度测试、XRD、光学金相、SEM、EDS等方法对合金时效过程中的合金相和显微组织的演变进行了研究。结果表明,450℃×12 h固溶和100℃时效后,合金随时效时间延长,晶内时效硬化效应增强,100℃时效3个月时达到硬化峰值87 HV。时效初期时合金晶内析出W相,随着时效时间的延长,合金晶内形成长周期结构χ(Mg12 YZn)相,并析出β′1(MgZn)相,且含量逐渐增多。长周期χ(Mg12YZn)相和细小针(棒)状的β′1(MgZn)相的形成是Mg-5Zn-0.6Zr-1RE-2Y合金低温时效强化的两个主要来源。Phase and microstructure evolution in as-cast Mg-5Zn-0.6Zr-1RE-2Y magnesium alloy solution-treated at 450 ℃ and then aged at 100 ℃ for different time was studied by means of micro-hardness test,XRD,optical microscopy,SEM and EDS analysis.The results show that the effect of intragranular age-hardening increases with increasing aging time after solution-treated at 450 ℃ for 12 h and aged at 100 ℃ for different time,the peak micro-hardness value of 87 HV is obtained after aging at 100 ℃ for 3 months.W phase precipitated in the intragranular during early aging at 100 ℃,the long-period structure χ（Mg12 YZn） phase and β′1（MgZn） phase form in the intragranular and its content increases with increasing aging time.Aging strengthening at low temperature of the alloy is due to the long-period χ（Mg12 YZn）phase and the needle（baseball）-like MgZn phase form in the intragranular.

关 键 词：Mg-Zn-Y系合金 显微组织 时效硬化 Mg12YZn MgZn 

分 类 号：TG146.223[一般工业技术—材料科学与工程]