Al_2O_(3sf)/AZ91D镁基复合材料等径角挤压变形机制研究  

Research on Deformation Mechanism of Al_2O_(3sf)/AZ91D Magnesium-based Composite during Equal Channel Angular Extrusion

作　　者：陈嫚丽[1,2] 朱世凤[1,2] 赵志翔[1,2] 宁海青[1,2] 

机构地区：[1]中国兵器工业第五九研究所,重庆400039 [2]国防科技工业精密塑性成形技术研究应用中心,重庆400039

出　　处：《精密成形工程》2011年第3期20-24,共5页Journal of Netshape Forming Engineering

摘　　要：为了推动半固态加工在镁基复合材料成形中的应用,采用液态浸渗法制备了增强体体积分数为5%的Al2O3sf/AZ91D复合材料,并采用等径角挤压对其实施变形。利用光学显微镜、扫描电镜和拉伸实验机分别对试样进行了组织观察和力学性能测试,并以此为基础探讨了复合材料在等径角挤压过程中的变形机制。研究表明:Al2O3sf/AZ91D 1道次挤压后,其基体是剪切变形后动态再结晶组织;当试样存在缺陷时,试样的变形机制除剪切变形外,同时还存在压缩变形;在等径角挤压过程中,由于试样在模具转角处的不均匀变形使得铸造缺陷消除的同时也产生了新的缺陷(裂纹)。因此,在等径角挤前应对复合材料进行密实变形,或采用低压浸渗和高压凝固复合技术,以消除制备过程中产生的铸造缺陷。To promote the application of semi-solid processing in the field of forming magnesium-based composites,in this paper,AZ91D composites reinforced with alumina fibers（5%） were manufactured by the liquid infiltration and then were deformed by equal channel angular extrusion（ECAE）.The microstructures and mechanical properties of samples were studied by optical microscope,SEM and tensile testing machine,respectively.Based on those,deformation mechanisms of the samples were also discussed during ECAE.The results show that the basal body of composites undergoing one pass shear deformation consists of dynamic recrystallisation structures after ECAE.However,there are both shear deformation and compression deformation,when there are some defects in samples.The inhomogeneous deformation of samples at turn angle of the die leads to eliminating casting defects and at the same time generating some new deficiencies,such as crack.Therefore,in order to eliminate casting defect during preparation,composites need to be compacted by low pressure infiltration and high pressure solidification before ECAE.

关 键 词：Al2O3sf/AZ91D 液态浸渗 等径角挤压 晶粒细化机制 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG379[金属学及工艺—金属材料]