Investigation of the interface deformation behavior of SiCp/Al composites via TEM in-situ tensile test

Abstract

As a “bridge” between the matrix and reinforcement, the interface plays a crucial role in the deformation behavior of SiCp/Al composites. It is of great significance to investigate the dynamic changes of dislocations and microcracks in the deformation process of the composite interface microzone. In situ tensile specimens with special interfaces containing different thicknesses of MgAl₂O₄ reaction layers were selected. In situ tensile tests were performed using field emission transmission electron microscopy. The effect of the interface layer thickness on the tensile deformation of the composites was revealed based on the crack initiation to propagation fracture. The results showed that the cracks first emerged at the SiC/Al interface, and then extend along the MgAl₂O₄/Al interface to the interface region of the MgAl₂O₄ reaction layer with a thickness of about 40 nm, eventually fracture occurs at the interface region with 70 nm thick MgAl₂O₄ reaction layer. Suitable thickness of MgAl₂O₄ reaction layer can effectively delay the crack propagation and improve the interface bonding strength between SiC and Al. The regulation of the thickness of the MgAl₂O₄ reaction layer is crucial for the mechanical properties of SiCp/Al composites.