Si添加对快速凝固/粉末冶金镁合金组织及力学性能的影响  

Effect of Si Addition on Microstructure and Mechanical Properties of Mg-Al-Zn-Mn Alloy Fabricated by Rapidly Solidification/Powder Metallurgy

作　　者：刘守法[1] 周兆锋[2] 刘丹成 LIU Shoufa;ZHOU Zhaofeng;LIU Dancheng(School of Mechanical Engineering,Xijing University,Xi'an 710123,China;School of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;Xi’an Space Engine Co.Ltd.,Xi’an 710100,China)

机构地区：[1]西京学院机械工程学院,西安710123 [2]南京航空航天大学机电学院,南京210016 [3]西安航天发动机有限公司,西安710100

出　　处：《有色金属工程》2019年第9期40-44,共5页Nonferrous Metals Engineering

基　　金：国家科技重大专项(2017ZX04011-010);陕西省教育厅专项科研计划项目(15JK2172)~~

摘　　要：采用快速凝固/粉末冶金工艺分别制备Mg-8Al-0.5Zn-0.15Mn及Mg-8Al-0.5Zn-0.15Mn-2Si合金挤压棒材。利用光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)及拉伸机,研究了Si添加对Mg-Al-Zn-Mn合金显微组织及室温力学性能的影响。结果表明,与热压Mg-Al-Zn-Mn合金相比,热压Mg-Al-Zn-Mn-Si合金内晶界上网状分布的Mg17Al12相减少,晶内出现多边形状Mg2Si相。热压后的反向挤压过程中Mg-Al-Zn-Mn合金与Mg-Al-Zn-Mn-Si合金组织均发生连续动态再结晶,其中Mg-Al-Zn-Mn-Si晶粒细化较好,伸长率较大,第二相Mg2Si与基体接合良好,但Mg2Si相周围出现的应力集中导致屈服强度和抗拉强度降低。随着反向挤压温度上升,反向挤压制备的两种合金屈服强度和抗拉强度均降低,而伸长率增大。Mg-8Al-0.5Zn-0.15Mn and Mg-8Al-0.5Zn-0.15Mn-2Si alloy extruded bars were prepared by rapidly solidification/powder metallurgy process. The effects of Si addition on the microstructure and room-tempreture mechanical properties of Mg-Al-Zn-Mn alloy were investigated by Optical Microscopy(OM), Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM), X-ray Diffractometry(XRD), and stretching machine. The results show that compared with the hot-pressed Mg-Al-Zn-Mn alloy, the Mg 17 Al 12 phase in the grain boundary of the hot-pressed Mg-Al-Zn-Mn-Si alloy decreases, and the polygonal Mg 2Si phase appears in the crystal. During the reverse extrusion process, Mg-Al-Zn-Mn alloy and Mg-Al-Zn-Mn-Si alloy undergo continuous dynamic recrystallization. Mg-Al-Zn-Mn-Si has fine crystal grains and large elongation, and the second phase Mg 2Si is well bonded to the matrix. However, the stress concentration around Mg 2Si phase leads to the decrease of yield strength and tensile strength. As the reverse extrusion temperature rises, both the yield strength and the tensile strength of the two reverse extruded alloys decrease, while the elongation increases.

关 键 词：快速凝固/粉末冶金 显微组织 力学性能 MG2SI相 反向挤压 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TB331[金属学及工艺—金属材料]