FRICTION AND WEAR OF COPPER REINFORCED BY UNIDIRECTIONAL CONTINUOUS FIBERS OF CHROMIUM NICKEL STEEL

The friction and wear of metal matrix composites consisting of oxygen free high purity copper matrix (OFHC) reinforced by circular fibres of chromium nickel steel (18.0 % Cr and 9.0 % Ni) of 0.2 mm diameter of different fibre volume fraction sliding against carbon steel surface w ere investigated For adhesive and abrasive wear tests as the fibre vol ume fraction in the composites increased wear decreased, The friction coefficient decreased with increasing the fibre volume Traction dawn t o a certain value then increased to attain chat for fibre material. Co mposites containing 66 % fibre volume fraction displayed minimum value s of friction, This behaviour has been discussed on the basis of lubri cation with a metallic film where the worn copper particles are presse d between the composite and steel surfaces forming copper film. The re lative sliding is facilitated by the shear of the copper film and the sliding resistance cannot exceed the shear strength of the copper. It was, also, found that increasing the sliding velocity of the composite s caused remarkable reduction in coefficient of friction doe to the fr ictional heating which may speed up oxidation rate forming oxide film responsible for this reduction.