轻质MgAlSnZnCu高熵合金的微观组织和力学性能  

Microstructure and mechanical properties of MgAlSnZnCu lightweight high entropy alloys

作　　者：杨拓宇 王克鸿[2] 张德库[2] 陈丰 郭纯 张雅晶 Yang Tuoyu;Wang Kehong;Zhang Deku;Chen Feng;Guo Chun;Zhang Yajing(School of Mechanical Engineering,Anhui Science and Technology University,Bengbu Anhui 233100,China;School of Material Science and Engineering,Nanjing University of Science and Technology,Nanjing Jiangsu 210094,China)

机构地区：[1]安徽科技学院机械工程学院,安徽蚌埠233100 [2]南京理工大学材料科学与工程学院,江苏南京210094

出　　处：《金属热处理》2022年第12期216-221,共6页Heat Treatment of Metals

基　　金：安徽省教育厅重点项目(KJ2020A0072);安徽科技学院自然科学项目(2021zrzd02)(100005)。

摘　　要：为了提高阻隔层的稳定性,研究采用电磁感应加热方法,在覆盖剂和氩气保护作用下制备MgAlSnZnCu系列轻质高熵合金。使用扫描电镜(SEM)、X射线衍射(XRD)、能谱分析(EDS)对合金的铸造组织、退火组织和物相进行了表征和分析,同时采用显微硬度测试方法对其硬度进行了研究。结果表明,铸态MgAlSnZnCu合金组织由(AlMgZnCu)-FCC相和Mg_(2)Sn相组成,Mg_(2)Sn相的形态为2~6μm粒状和不规则块状。Mg的含量由22%降低到12%,其合金的硬度由277 HV0.2增加到326 HV0.2,抗压强度由223 MPa增加到237 MPa。Sn和Zn含量降低后组织中出现了针状和片状的杂质相,且硬度值分散度较大,在450℃保温6 h的退火工艺条件下,组织中的杂质相出现明显的积聚长大的趋势。力学性能测试显示退火对抗压强度和硬度的影响不大,MgAlSnZnCu系列合金在450℃的条件下能保持较好的热稳定性。In order to improve the stability of the barrier layer,MgAlSnZnCu series of lightweight high entropy alloys were prepared by electromagnetic induction heating method under the protection of a covering agent and argon gas.The as-cast microstructure,annealed microstructure and phases of the alloys were characterized and analyzed by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),energy spectrum analysis(EDS),and microhardness test was used to study its hardness.The results show that the microstructure of as-cast MgAlSnZnCu alloy is composed of(AlMgZnCu)-FCC phase and Mg_(2)Sn phase.The morphology of Mg_(2)Sn phase is 2-6μm granular and irregular block.When the content of Mg decreases from 22%to 12%,the hardness of the alloy increases from 277 HV0.2 to 326 HV0.2,and the compressive strength increases from 223 MPa to 237 MPa.Needle-like and flake-like impurity phases appear in the microstructure after the decrease of Sn and Zn contents,and the dispersion of hardness values is large,after annealing at 450℃for 6 h,the impurity phases in the microstructure tend to accumulate and grow obviously.The mechanical test results show that the annealing have little effect on compressive strength and hardness.The MgAlSnZnCu series alloys can maintain good thermal stability at 450℃.

关 键 词：轻质高熵合金 扩散退火 组织 维氏硬度 抗压强度 

分 类 号：TG146.4[一般工业技术—材料科学与工程]