Si添加对粉末冶金AZ80合金组织及高温力学性能的影响  

Effect of Si addition on microstructure and high temperature mechanical properties of powder metallurgy AZ80 alloy

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 Shaanxi 710123,China;School of Mechanical and Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing Jiangsu 210016,China;Xi’an Space Engine Co.,Ltd.,Xi’an Shaanxi 710100,China)

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

出　　处：《金属热处理》2019年第11期30-34,共5页Heat Treatment of Metals

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：采用熔铸法分别制备AZ80合金及AZ80-Si合金,随后依次采用双气流雾化、热压和反向挤压工艺对两种合金进行加工,利用光学显微镜、SEM、XRD及拉伸机,研究Si添加对AZ80合金组织及高温力学性能的影响。研究表明:与双气流雾化AZ80合金颗粒相比,AZ80-Si合金颗粒内网格状分布的Mg17Al12相减少而多边形颗粒状分布的Mg2Si相增多。反向挤压过程中两种热压合金组织均发生连续动态再结晶,反向挤压AZ80-Si合金晶粒细化较好,内部Mg2Si颗粒与基体相冶金接合良好,拉伸过程中起到了钉扎作用,使其屈服强度和抗拉强度均提升较大,但伸长率较小;AZ80断口组织呈现解理台阶状,而AZ80-Si由于高温强化相Mg2Si的作用,断口组织为较大且深的韧窝。AZ80 and AZ80-Si alloy were fabricated respectively by melting-casting method.Then the alloy was processed by double-gas flow atomizing,hot pressing and reverse extrusion.Effect of Si addition on the microstructure and high temperature mechanical properties of AZ80 alloy was investigated by means of optical microscopy,SEM,XRD and tensile machine.The results show that Mg17Al12 phase with grid-like distribution in the AZ80-Si alloy particles is reduced and the Mg2Si phase with polygonal particle distribution is increased compared with the double-gas-flow atomized AZ80 alloy particles.During the reverse extrusion process,the two hot-pressed alloys undergo continuous dynamic recrystallization.The grains of AZ80-Si are refined well by reverse extrusion,and the Mg2Si grains are metallurgically bonded well with the matrix,which plays a pinning role in the tensile process,and the yield strength and tensile strength increases greatly,but the elongation is small.Fracture structure of the AZ80 alloy shows a dissociation step,where as fracture structure of the AZ80-Si alloy consists of larger and deeper dimples due to the action of high temperature strengthening of phase Mg2Si.

关 键 词：AZ80合金 熔铸法 粉末冶金 双气流雾化 反向挤压 力学性能 

分 类 号：TG379[金属学及工艺—金属压力加工]