Abstract: In order to research the interfacing connection mechanism between the reinforced particles and metal matrix of the metal matrix composites in a severe plastic deformation (SPD) process, equal channel angular pressing and torsion (ECAP-T) process was used to fabricate bulk 10wt% SiC_P/Al matrix composites at lower heating temperature. And the interfacial reaction and element diffusion between SiC particles and pure Al, occurred by deformation of ECAP-T one, two and four passes, were investigated. The interface and element diffusion were studied by TEM and XPS. Results show that even at a lower processing temperature outside, Al can still react with SiO₂ layer on the SiC particle surfaces and form an interface layer mainly made of Al₂O₃. The diffusion coefficient of Al is enhanced by about 10¹⁶ times during the ECAP-T deformation in comparison with the theoretically calculated value. The enhanced diffusion attribute to not only the increase of interface temperature but also the presence of a high density of lattice defects such as vacancies, dislocations produced by ECAP-T deformation.