Segregation-modified Interfacial Strength and Deformation Mechanism at SiCp/2009Al Composite Interface

The reinforcement/matrix interface is a crucial factor affecting the mechanical performance of metal matrix composites (MMCs). However, it is difficult to quantitatively characterize the correlation between interfacial microstructure and mechanical properties, especially between interfacial segregation and interfacial strength. In this study, composite micro-pillars containing a single slanted interface with Mg segregation were fabricated in engineering SiCp/2009Al composites produced by the powder metallurgy technique (PMT). Upon uniaxial compression, changes in interfacial deformation behavior depended on the Mg segregation amount. Specifically, as the segregation amount increased, the interfacial shear strength increased from 174.5 MPa to 230 MPa, and the misorientation angles of the interfacial micro-region increased from 1.2 +/- 0.5 degrees to 8.8 +/- 5.6 degrees. It was demonstrated that the Mg segregation in the SiC/Al interface can considerably enhance interfacial adhesion by improving interfacial wettability, and the interfacial micro-region with stronger interfacial adhesion can endure more external strain through grain fragmentation.