Acta Metallurgica Sinica (English Letters) ›› 2024, Vol. 37 ›› Issue (3): 438-452.DOI: 10.1007/s40195-024-01669-1

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Tailoring the Microstructure and Mechanical Property of Mg-Zn Matrix Composite via the Addition of Al Element

Chong Wang1, Fuyuan Liu1, Xuejian Wang2, Enyu Guo1,3(), Zelong Du1, Kunkun Deng4, Zongning Chen1,3, Huijun Kang1,3, Guohao Du5, Tongmin Wang1,3()   

  1. 1Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
    2School of Mechanical Engineering, Guizhou University, Guiyang 550025, China
    3Ningbo Institute of Dalian University of Technology, Ningbo 315000, China
    4Shanxi Key Laboratory of Advanced Magnesium-Based Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
    5Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute CAS, Shanghai 201204, China
  • Received:2023-10-31 Revised:2023-12-04 Accepted:2023-12-28 Online:2024-03-10 Published:2024-02-17
  • Contact: Enyu Guo, eyguo@dlut.edu.cn;Tongmin Wang, tmwang@dlut.edu.cn

Abstract:

The semi-solid stir casting method is adopted to prepare 10 wt% SiCp/Mg-6Zn-0.5Ca-xAl (x = 0, 1, 3 and 5 wt%) composites, and the microstructure evolution and mechanical property of composites with various Al content are investigated. The results show that the addition of 3 wt% Al improves the distribution of SiCp, whereas the SiCp cluster occurs again with Al content greater than 3%. An abnormal phenomenon of twinning is observed in the cast composites in this work. The SiCp/Mg-6Zn-0.5Ca composite possesses the highest twin content of ~ 23%, for which tension twins (TTW) and compression twins (CTW) account for ~ 19% and ~ 3%, respectively. The CTW is only observed in ZXA600 composite. The addition of Al has an inhibiting effect for the generation and growth of twins. The content of twin decreases firstly and then increases with increase of Al content. The lowest twin content is obtained as Al increases to 3 wt%. It is found the existence of twin is detrimental to the mechanical property of composites. As-cast SiCp/Mg-6Zn-0.5Ca-3Al composite with the lowest twin content exhibits the optimal mechanical property of yield strength, ultimate tensile strength and elongation for 100 MPa, 188 MPa and 4.4%, respectively. The outstanding mechanical property is attributed to the uniform distribution of SiCp, the low twin content and the well-distributed fine second phases.

Key words: Mg matrix composite, Synchrotron tomography, Twinning, Liquid melt processing, Mechanical property