In-situ synthesis and chemical bonding of the Al-doped β-SiC particles in Al-Si-C light alloys

Abstract

In this work, the Al-doped β-SiC particles are in-situ synthesized in Al-20Si-5C alloys using the novel liquid–solid multiphase reaction method. The morphological evolution with changed Al doped β-SiC particles has been carefully investigated, and it is observed that the β-SiC transforms from the hexagonal flake to the truncated pyramid and finally evolves to the irregular polyhedral with the decrease of Al doping in SiC. The influence mechanism of the Al doped amount of SiC on the Brinell hardness and wear resistance of the Al doped SiCp reinforced aluminum matrix composites has been explored. Furthermore, the density functional theory (DFT) calculations of the chemical structures of doped SiCp with different Al doping levels indicate the covalent bond proportion in SiCp and the electron density around carbon atoms are all decreased as the increase of the Al doping content. It is also found that the Young’s modulus and Vickers hardness of doped SiCp decrease as the Al doping content increases by DFT calculations. It is proposed that this work paves a new way to improve the properties of aluminum matrix composites by regulating the doped level and chemical bonding of reinforcing particles for potential light weighting applications.