Microstructure, hardness and wear behaviour of NbC reinforced AA7075 matrix composites fabricated by friction stir processing

Abstract

Abstract Aluminium alloy AA7075 matrix composites reinforced with different vol.% of niobium carbide were fabricated by friction stir processing. Microstructural investigations of the composites as well as the interface between AA7075 and NbC were conducted using optical microscopy and scanning electron microscopy. SEM micrographs revealed a homogeneous dispersion of NbC in the AA7075 matrix in all the composites. SEM studies also revealed very good bonding of the dispersoid particles with the matrix along with significant degree of grain refinement. Hardness and wear resistance of AA7075 matrix was enhanced both by the addition of NbC particles as well as grain refinement. Wear behaviour studies showed that predominant wear mechanisms were abrasive wear and adhesive wear.