Microstructure and mechanical properties of in-situ α-Al2O3p/Al-12Si composites fabricated by direct melt reaction method with aid of electromagnetic stirring

作者：Xu, Jinkang; Chen, Gang^*; Zhang, Zhenya; Zhao, Yutao; Zhou, Xiang; Zhang, Zailei; Meng, Mingai; Liu, Xin; Yan, Qing

来源：Materials Research Express, 2018, 5(11): 116502.

DOI：10.1088/2053-1591/aadbee

• alpha-Al2O3p/Al-12Si composites
• direct melt reaction method
• electromagnetic stirring
• microstructure
• mechanical properties

Herein, we successfully fabricated in situ alpha-Al2O3p/Al-12Si composites by direct melt reaction method from Al-SiO2 system with aid of electromagnetic stirring. Through thermodynamics analysis, it was demonstrated that the aluminum (Al) melt and SiO2 powders were firstly reacted at 755.8 degrees C to form metastable gamma-Al2O3 and then converted to stable alpha-Al2O3 at 1045.6 degrees C. Microstructure observations showed that electromagnetic stirring was effective to suppress the alpha-Al2O3 particle agglomerations in 5 vol% alpha-Al2O3p/Al-12Si composite, and the alpha-Al grains in the Al-12Si matrix alloy were greatly refined by the well dispersed in situ alpha-Al2O3 particles. The ultimate tensile strength (UTS), Brinell hardness and elongation of the T6-treated 5 vol% alpha-Al2O3p/Al-12Si composite were 325 MPa, 145 HB and 2.5%, respectively. Compared with those of the Al-12Si alloy, the UTS and Brinell hardness increased by 10.9% and 16%, while elongation decreased by 36.0%. Furthormore, it was found that the high temperature UTS of the above composite was higher than that of the Al-12Si matrix alloy at the temperature ranging from 25 to 350 degrees C, and the contribution rate (K) of the in situ alpha-Al2O3 particles to the UTS reached its maximum value (34.3%) at 300 degrees C. Taken together, the in situ 5 vol% alpha-Al(2)O(3)p/Al-12Si composite with high strength at both room temperature and high temperature is very promising as the piston material.

• 出版日期2018-11
• 单位江苏大学