Acta Metall Sin  2019, Vol. 55 Issue (10): 1319-1328    DOI: 10.11900/0412.1961.2018.00523
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Effect of Hot Pressing Temperature on Microstructure and Tensile Properties of SiC/Al-Zn-Mg-Cu Composites
MA Guonan1,2,WANG Dong1(),LIU Zhenyu1,BI Sheng1,2,ZAN Yuning1,2,XIAO Bolv1,MA Zongyi1
1. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
2. School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
Abstract

Particulate reinforced aluminum matrix composites have been widely used in industrial fields. In general, high strength aluminium alloys, such as 2024Al are employed to produce stronger composites. However, the composites with high strength Al-Zn-Mg-Cu alloys as the matrices are paid relative attentions. Therefore, the corresponding optimization for fabrication parameters has not been well understood. In the present work, SiC particles with volume fraction of 15% reinforced Al-7.5Zn-2.8Mg-1.7Cu (mass fraction, %) composites were fabricated using powder metallurgy (PM) technique at hot pressing temperatures of 500, 520, 540 and 560 ℃. TEM, EPMA and tensile test were used to study the effect of hot pressing temperature on the microstructure and tensile properties of SiC/Al-Zn-Mg-Cu composites. The measured densities indicated that all the composites were completely condensed, no pores were observed. Undissolved phase containing Mg and Cu segregated in matrix of the composites hot pressed at 500 and 520 ℃, resulting in instable tensile properties. With increasing hot pressing temperature to 540 ℃, Mg and Cu were uniformly distributed in the composites which exhibited the stable tensile properties. With further increasing temperature to 560 ℃, Mg segregated around SiC particles due to interface reaction. In this case, the content of MgZn2 phase was decreased, resulting in the reduction of tensile strength. HAADF-STEM and EDS analyses showed that the interface compounds were oxide of Mg and coarse MgZn2 phase.

 ZTFLH: TG146.2
Fund: National Key Research and Development Program of China(52017YFB0703104);National Natural Science Foundation of China(51771193);National Natural Science Foundation of China(U1508216)
Corresponding Authors:  Dong WANG     E-mail:  dongwang@imr.ac.cn
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