Microstructure and mechanical properties of AZ31-Mg_2Si in situ composite fabricated by repetitive upsetting  

反复镦压AZ31-Mg_2Si原位复合材料的组织和力学性能(英文)

作　　者：郭炜[1,2] 王渠东[1,2] 叶兵[1,2] 周浩[1] 刘鉴锋[1] 

机构地区：[1]上海交通大学轻合金精密成型国家工程研究中心,上海200240 [2]上海交通大学金属基复合材料国家重点实验室,上海200240

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第12期3755-3761,共7页中国有色金属学报（英文版）

基　　金：Projects(51074106,51374145)supported by the National Natural Science Foundation of China;Project(09JC1408200)supported by the Science and Technology Commission of Shanghai Municipality,China;Project(2014M561466)supported by China Postdoctoral Science Foundation;Project(14R21411000)supported by Shanghai Postdoctoral Scientific Program,China

摘　　要：AZ31-4.6% Mg2Si （mass fraction） composite was prepared by conventional casting method. Repetitive upsetting （RU） was applied to severely deforming the as-cast composite at 400 ℃ for 1, 3, and 5 passes. Finite element analysis of the material flow indicates that deformation concentrates in the bottom region of the sample after 1 pass, and much more uniform deformation is obtained after 5 passes. During multi-pass RU process, both dendritic and Chinese script type Mg2Si phases are broken up into smaller particles owing to the shear stress forced by the matrix. With the increasing number of RU passes, finer grain size and more homogeneous distribution of Mg2Si particles are obtained along with significant enhancement in both strength and ductility. AZ31-4.6%Mg2Si composite exhibits tensile strength of 284 MPa and elongation of 9.8%after 5 RU passes at 400 ℃ compared with the initial 128 MPa and 5.4%of original AZ31-4.6%Mg2Si composite.采用常规铸造方法制备AZ31-4.6%Mg2Si复合材料,在400°C对铸态复合材料进行1、3和5道次的反复镦压(RU)剧烈变形。材料流动的有限元分析表明:1道次后变形集中于试样底部区域,5道次后可获得均匀的变形。多道次反复镦压过程中基体施加的剪切应力使树枝状和汉字状Mg2Si相破碎成小颗粒,随着反复镦压道次的增加,晶粒尺寸逐渐减小,Mg2Si颗粒分布逐渐均匀,同时强度和塑性显著提高,在400°C反复镦压5道次后,AZ31-4.6%Mg2Si复合材料抗拉强度和伸长率分别为248 MPa和9.8%,而原始铸态复合材料的抗拉强度和伸长率分别只有128 MPa和5.4%。

关 键 词：AZ31-Mg2Si composite Mg2Si particle repetitive upsetting microstructure mechanical properties 

分 类 号：TB33[一般工业技术—材料科学与工程] TG306[金属学及工艺—金属压力加工]