A novel modifier on the microstructure and mechanical properties of Al-7Si alloys

In this work, the AlCoCrFeNiTi high-entropy alloy (HEA) was prepared as an inoculant to refine the alpha-Al and silicon phases in Al-7Si alloy. The modification mechanism and the existing form of HEA in Al-7Si alloy were studied. The results show that Fe-rich intermetallics including Al, Si, Co, Fe and Ni, precipitated when the 0.2% AlCoCrFeNiTi HEA was added into Al-7Si alloy. In addition, the elements of Ti and Cr uniformly distributed within Al-7Si alloy. The morphology of the eutectic silicon changed from long needle structure to short rod and granular structure. Moreover, the size of alpha-Al grains significantly decreased in Al-7Si-0.2HEA alloy. The mechanical properties of Al-7Si alloy significantly improved. (C) 2019 Elsevier B.V. All rights reserved.