Self-lubricating bidirectional carbon fiber reinforced smart aluminum composites by squeeze infiltration process

Abstract

Self-lubrication is one of the smart material properties required for producing components with enhanced wear resistance and low coefficient of friction. Bidirectional (BD) satin weave polyacrylonitrile (PAN) based carbon fiber (Cf) fabric preform was successfully infiltrated with Al 6061 alloy by squeeze infiltration process. The infiltrated composite shows uniform distribution of carbon fibers in the matrix with the elimination of porosities, fiber damage and close control on the formation of deleterious aluminum carbide (Al4C3) phase. Cf/Al composite exhibits remarkable wear resistance compared to unreinforced alloy due to the formation of self-lubricating tribolayer on the pin surface, which intercepts the contact of matrix metal to counter surface. The BD carbon fiber enhanced the hardness and compressive strength of the composite by restraining the plastic flow behavior of matrix. High resolution transmission electron microscopy shows the presence of Al2O3 and MgAl2O4 spinel, confirmed by EDS and SAD pattern, at the composite interface. The composite shows a lower density of 2.16 g/cm3 which is a major advantage for weight reduction compared to the monolithic alloy (2.7 g/cm3).