Abstract:Powder mixture of pure Al and oxidized SiC was consolidated into 10% (mass fraction) SiC_p/Al composites at 250 °C by equal channel angular pressing and torsion (ECAP-T). The valence states of Si for SiC particulates and Al for the as-consolidated composites were detected by X-ray photoelectron spectroscopy (XPS). The interfacial bondings of the composites were characterized by scanning electron microscopy (SEM). The elements at the interface were linearly scanned by energy dispersive spectroscopy (EDS) and the EDS mappings of Si and Al were also obtained. The values of the nanohardness at different positions within 2 μm from the boundary of SiC particulate were measured. The results show that after ECAP-T, interfacial reaction which inhibits injurious interfacial phase occurs between Al and the oxide layer of SiC, and the element interdiffusion which can enhance interfacial bonding exists between Al and SiC. As ECAP-T passes increase, the reaction degree is intensified and the element interdiffusion layer is thickened, leading to the more smooth transition of the hardness from SiC to Al.

Key words: metal matrix composites; consolidation; deformation; interfacial reaction; element interdiffusion