Microstructure evolution,mechanical properties and fracture behavior of Al-xSi/AZ91D bimetallic composites prepared by a compound casting  

作　　者：Guangyu Li Wenming Jiang Feng Guan Junwen Zhu Yang Yu Zitian Fan 

机构地区：[1]State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China

出　　处：《Journal of Magnesium and Alloys》2024年第5期1944-1964,共21页镁合金学报（英文）

基　　金：the supports provided by the National Natural Science Foundation of China(Nos.52075198 and 52271102);the China Postdoctoral Science Foundation(No.2021M691112);the State Key Lab of Advanced Metals and Materials(No.2021-ZD07);the Analytical and Testing Center,HUST。

摘　　要：In this paper,the effect of the Si content on microstructure evolution,mechanical properties,and fracture behavior of the Al-xSi/AZ91D bimetallic composites prepared by compound casting was investigated systematically.The obtained results showed that all the Al-xSi/AZ91D bimetallic composites had a metallurgical reaction layer(MRL),whose thickness increased with increasing Si content for the hypoeutectic Al-Si/AZ91D composites,while the hypereutectic Al-Si/AZ91D composites were opposite.The MRL included eutectic layer(E layer),intermetallic compound layer(IMC layer)and transition region layer(T layer).In the IMC layer,the hypereutectic Al-Si/AZ91D composites contained some Si solid solution and flocculent Mg_(2)Si+Al-Mg IMCs phases not presented in the hypoeutectic Al-Si/AZ91D composites.Besides,increasing Si content,the thickness proportion of the T layer increased,forming an inconsistent preferred orientation of the MRL.The shear strengths of the Al-xSi/AZ91D bimetallic composites enhanced with increasing Si content,and the Al-15Si/AZ91D composite obtained a maximum shear strength of 58.6 MPa,which was 73.4% higher than the Al-6Si/AZ91D composite.The fractures of the Al-xSi/AZ91D bimetallic composites transformed from the T layer into the E layer with the increase of the Si content.The improvement of the shear strength of the Al-xSi/AZ91D bimetallic composites was attributed to the synergistic action of the Mg_(2)Si particle reinforcement,the reduction of oxidizing inclusions and the ratio of Al-Mg IMCs as well as the orientation change of the MRL.

关 键 词：Al/Mg bimetallic composites Si content Mg_(2)Si reinforcement Microstructure Mechanical properties Fracture behavior 

分 类 号：TG24[金属学及工艺—铸造] TB331[一般工业技术—材料科学与工程]