Effect of Y on age hardening response and mechanical properties of Mg-xY-1.5LPC-0.4Zr alloys  

钇含量对Mg-xY-1.5LPC-0.4Zr合金的时效硬化和力学性能的影响(英文)

作　　者：王军[1,2] 聂景江[1] 王荣[1] 徐永东[1] 朱秀荣[1] 凌国平[2] 

机构地区：[1]中国兵器科学研究院宁波分院,宁波315103 [2]浙江大学材料科学与工程系,杭州310027

出　　处：《Transactions of Nonferrous Metals Society of China》2012年第7期1549-1555,共7页中国有色金属学报（英文版）

基　　金：Project(2010A6100153)supported by Natural Science Foundation of Ningbo,China

摘　　要：Ageing hardening,microstructure and mechanical properties of Mg-xY-1.5LPC-0.4Zr（x=0,2,4,6）alloys（LPC represents La-based rare earth metal）were investigated.It was found that the age hardening was enhanced,the grains became finer and the tensile strength was improved with the increase of Y content in Mg-Y-1.5LPC-0.4Zr alloy.The results show that the formed precipitates responsible for age hardening change from fine hexagonal-shaped equilibrium Mg12RE phase to metastableβ′phase with orthorhombic-bc crystal structure when Y is added into Mg-1.5LPC-0.4Zr alloy,and the volume fraction of precipitate phases also increases.The cubic-shapedβ-Mg24Y5 precipitate phases were also observed at grain boundaries in Mg-6Y-1.5LPC-0.4Zr alloy. The distribution of prismatic shapedβ′phases and cubic shapedβ-Mg24Y5 precipitate phases in Mg matrix may account for the remarkable enhancement of tensile strength of Mg-Y-LPC-Zr alloy.The Mg-6Y-1.5LPC-0.4Zr alloy exhibits maximum tensile strength at peak-aged hardness,and the values are 250 MPa at room temperature and 210 MPa at 250°C.研究钇含量对Mg-xY-1.5LPC-0.4Zr镁合金的时效硬化、显微组织和力学性能的影响(其中LPC代表富镧混合稀土金属)。当将Y加入Mg-1.5LPC-0.4Zr时,随着Y含量的增加,合金的时效硬化反应相应增强,晶粒尺寸变小,强度增加。当将Y添加到Mg-1.5LPC-0.4Zr合金中时,时效析出相发生改变,由Mg-LPC基合金的稳态Mg12RE相转变为Mg-Y基合金的亚稳态β′相,且随着Y含量的增加,β′相的数量也相应增多。在合金晶界上还发现了稳态立方形的β-Mg24Y5相。对于Mg-Y-LPC-Zr合金,拉伸性能的改善主要归功于均匀、弥散分布的β′相,在晶界上的β-Mg24Y5相对合金的晶界也有明显的强化作用。当Y含量达到6%时,合金的拉伸强度最大,合金在室温和250°C的抗拉强度分别是250 MPa和210 MPa。

关 键 词：magnesium alloy rare earth YTTRIUM age hardening precipitate phases 

分 类 号：TG156.92[金属学及工艺—热处理]