Effects of surface-oxidation modification and heat treatment on silicon carbide 3D/AlCu ₅ MgTi composites during vacuum-pressure infiltration

Interfacial and metal phases influence the mechanical properties of Al matrix composite reinforced with three-dimensional SiC skeleton. Surface-oxidation modification and heat treatment are the most suitable methods of improving interfacial and metal phases. This study shows that heat treatment deposits CuAl ₂ phase into Al phase to improve material structure and stress distribution from the perspective of metal phase. Thus, compression strength increases with increased solid-solution time and temperature. From the perspective of interfacial phase, short contact time accounts for the decreased bending strength of leaf-shaped Al ₂ SiO ₅ without solid solution. However, with solid solution, Al-O-Si excessive layer improves bending strength with increased temperature. Thus, failure location is converted from SiC/Al interface to SiC phase, which is the most important influence of solid solution. Moreover, if solid-solution time is considerably long, Al-O-Si excessive layer thickness is sufficient to decrease the bending strength of the composites.