低温慢速挤压和电脉冲处理制备具有优异力学性能的AZ91双峰合金  

Mechanical Properties of Bimodal AZ91 Alloy Prepared by Low-Temperature Slow Rate Extrusion and Electrical Pulse Treatment

作　　者：武红飞 樊建锋[1,2] 单召辉 张华 张强[1,2] 邓坤坤 吴玉程[1] 李卫国 董洪标 许并社 Wu Hongfei;Fan Jianfeng;Shan Zhaohui;Zhang Hua;Zhang Qiang;Deng Kunkun;Wu Yucheng;Li Weiguo;Dong Hongbiao;Xu Bingshe(Key Laboratory of Interface Science and Engineering in Advanced Materials,Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Advanced Magnesium-based Materials,Taiyuan 030024,China;Department of Engineering,University of Leicester,Leicester LE17RH,UK)

机构地区：[1]太原理工大学新材料界面科学与工程教育部重点实验室,山西太原030024 [2]山西省先进镁基材料重点实验室,山西太原030024 [3]莱斯特大学工程系,英国莱斯特LEI7RH

出　　处：《稀有金属材料与工程》2021年第3期807-815,共9页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(U1710118,U1810122,51504162,51601123);Outstanding Innovative Teams of Higher Learning Institutions of Shanxi(2018);Natural Science Foundation of Shanxi Province(201801D221139);Shanxi Scholarship Council of China(2016-029)。

摘　　要：通过低温慢速挤压(LTSRE)和电脉冲处理(EPT)获得具有双峰结构的AZ91镁合金,这种结构由粗大的尺寸为20~60μm的未再结晶晶粒和细小的尺寸约为200 nm的再结晶晶粒组成。双峰晶粒结构的形成原因主要是LTSRE过程中的不均匀变形以及EPT对于变形AZ91镁合金静态再结晶的加速效应。与常规热处理时的静态再结晶过程相比,EPT过程的再结晶温度显著降低,处理时间明显缩短,有效抑制了再结晶晶粒的生长。同时在EPT过程中析出了大量形状规则的Mg17Al12相,平均尺寸约为200 nm。因此,本研究获得了屈服强度为463MPa和抗拉强度为527MPa的AZ91双峰合金,这主要归功于双峰组织以及细晶强化、析出强化和加工硬化的共同作用。Low-temperature slow rate extrusion(LTSRE)and electrical pulse treatment(EPT)were used to obtain the AZ91 Mg alloy with bimodal microstructure.Results show that the alloy consists of coarse unrecrystallized grains of 20~60μm and fine recrystallized grains of~200 nm.The bimodal grains contribute to the inhomogeneous deformation under LTSRE and the acceleration effect of the static recrystallization of the deformed AZ91 magnesium alloy under EPT.In addition,the growth of the recrystallized grains is effectively restrained due to the notably low recrystallization temperature and short processing time,compared with those of the conventional static recrystallization by heat treatment.Meanwhile,abundant Mg17 Al12 phases with an average size of 200 nm and regular shapes are precipitated during EPT.Consequently,the yield strength of 463 MPa and ultimate tensile strength of 527 MPa were acquired for the bimodal AZ91 alloy,which can be primarily attributed to the bimodal microstructure as well as the combined effect of fine grain strengthening,precipitation strengthening and work hardening.

关 键 词：AZ91镁合金 低温慢速挤压 电脉冲处理 双峰组织 力学性能 

分 类 号：TG146.22[一般工业技术—材料科学与工程]