Fabrication of Semisolid Billets of Hypereutectic Al-Si Alloy by Severe Plastic Deformation and Remelting

Abstract

This paper preliminarily explored and proved the feasibility of fabricating semisolid thixoforming billets for a hypereutectic Al-Si alloy (AlSi29Fe3) by severe plastic deformation (SPD) and semisolid remelting. In this paper, friction stir processing (FSP) was used to refine the coarse primary silicon particles and needle-shaped iron-rich phase of the hypereutectic Al-Si alloy. The results show that the semisolid thixoforming billets obtained by the above route contain fine spherical Al grains with mean size of 34m, and second-phase particles (both primary silicon and iron-rich intermetallic) of less than 10m. The microstructure is ideal non-dendritic semisolid structure. Therefore, SPD and remelting is a promising technology for the fabrication of semisolid thixoforming billets of the hypereutectic Al-Si alloy.