热处理对铜模铸造Mg-Yb-Zn-Zr合金结构性能研究  

Effect of Heat Treatment on Structure and Properties of Mg-Yb-Zn-Zr Alloy by Copper Mold Casting

作　　者：张亚琴 张德平 孟健[3] 程丽任[3] 张景怀 张栋栋 管凯 Zhang Yaqin;Zhang Deping;Meng Jian;Cheng Liren;Zhang Jinghuai;Zhang Dongdong;Guan Kai(Department of Mechanical Engineering,Taiyuan Institute of Technology,Taiyuan 030000,China;Department of Materials Science and Engineering,Jinzhong University,Jinzhong 030600,China;State Key laboratory of Rare Earth Resources Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;Key Laboratory of Superlight Materials&Surface Technology,Ministry of Education,Harbin Engineering University,Harbin 150001,China;Department of Materials Engineering,The University of Tokyo,Tokyo 113-8656,Japan)

机构地区：[1]太原工业学院机械工程系,山西太原030008 [2]晋中学院材料科学与工程系,山西晋中030619 [3]中国科学院长春应用化学研究所稀土资源利用国家重点实验室,吉林长春130000 [4]哈尔滨工程大学材料科学与化学工程学院,黑龙江哈尔滨150001 [5]东京大学材料工程系,日本东京113-8656

出　　处：《中国稀土学报》2022年第4期641-649,共9页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(52071093,51871069);山西省高等学校科技创新项目(2020L0631);太原工业学院博士启动基金项目(18/00006208)资助。

摘　　要：通过差热扫描量热分析(DSC)、光学显微镜(OM)、X射线衍射分析(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)和力学性能测试等方法,研究了热处理对铜模铸造Mg-Yb-Zn-Zr合金结构性能的影响。结果表明,铸态合金主要由α-Mg和Mg_(2)Yb相组成,固溶处理之后,Mg_(2)Yb相完全溶入到基体中且晶粒并未发生明显长大,晶内仅存有少量的Zn-Zr相。200℃峰时效合金中主要析出均匀分布于晶界附近连续链状和离散的Mg_(2)Yb相,同时还发现了一种在尺度和分布密度上存在差异的超细小针状析出相,基于高分辨透射电镜分析为γ'相(MgZnRE,六方结构,a=0.55 nm和c=0.52 nm)。峰时效合金展现了最好的力学性能,其抗拉强度、屈服强度和断后伸长率分别为258,136 MPa和10.7%。峰时效合金的强化机制为沉淀析出强化,其主要的强化效果来自于弥散分布细小的Mg_(2)Yb相和γ'相。The effects of heat treatment on the structure and properties of Mg-Yb-Zn-Zr alloy were studied by differential scanning calorimetry(DSC),optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),high resolution transmission electron microscopy(HRTEM)and mechanical properties test.The results indicated that the as-cast alloy is mainly comprised ofα-Mg and Mg_(2)Yb.After solution treatment,Mg_(2)Yb phase completely dissolves into Mg matrix,and the grains do not grow obviously.There is only a small amount of Zn-Zr phase in the grains.Continuous chain and discrete Mg_(2)Yb phases are mainly precipitated in peak-aged alloy at 200℃,and an ultrafine needle-like precipitate with different size and distribution density is also found,which isγ'phase according to the analysis of high resolution transmission electron microscope(Mg⁃ZnRE,hexagonal structure,a=0.55 nm and c=0.52 nm).The peak-aged alloy displays the best mechanical prop⁃erties with ultimate tensile strength of 258 MPa,yield strength of 136 MPa and elongation to failure of 10.7%.The dominant strengthening effect in peak-aged alloy is considered as precipitation strengthening induced by the dispersed fine Mg_(2)Yb andγ'phase.

关 键 词：Mg-Yb 铜模铸造 显微组织 力学性能 析出相 

分 类 号：TG146.2[一般工业技术—材料科学与工程]