Microstructure analysis and electro-controlled tribological properties of extruded SiC/6092Al composites

This study investigates the SiC/Al interfacial bonding and matrix grain orientation, and elucidates the mechanism of electric field-induced friction enhancement through temperature and electrorheological effects. Extruded SiC/6092Al composites were fabricated by powder metallurgy and hot extrusion. Grain features, microstructure, physical properties, and electro-controlled friction and wear behavior were characterized. Recovered grains in the Al matrix promote the ∥TD texture. SiC particles are uniformly dispersed throughout the matrix without agglomeration. At the SiC/Al interface, SiC atoms conform to the XYX and X-0.5X-X distribution patterns. Precipitation of β and Q phases is observed in the Al matrix. Application of an external voltage significantly enhances the friction coefficient of the specimens. Specifically, the increments in friction coefficient for specimens J1, J2, and J3 are 0.075, 0.143, and 0.109, respectively. The friction-increasing effect of the electric field exhibits characteristics of immediacy, abruptness, and reversibility. The synergistic mechanism of temperature and electrorheological effects in electrically controlled friction enhancement is systematically explained. Furthermore, the wear mechanism of composites is analyzed. SiC reinforcement enhances wear resistance. In the absence of an electric field, the dominant wear modes are plowing and fatigue spalling; under an applied electric field, plowing and adhesive wear become the primary mechanisms.