Abstract: The steady state friction and wear behavior of the as cast and T6 treated Al 18 B 4O 33 whisker reinforced AC4C Al composites was investigated with a block on ring apparatus under dry sliding conditions. The results indicate that the interfacial reaction between the whisker and the matrix influences the friction and wear of the composites. In the tested load range, all materials undergo a transition from mild wear to severe wear. Severe interfacial cracking and fracture and detachment of whisker occur due to the strain hardening of the surface and subsurface layer under the high load,accompanied by scuffing and adhesion. Compared with the as cast composite, T6 treated composite with reduced whisker hardness and strength and brittle and weak whisker matrix interface has relatively low wear resistance. Under low load and sliding speed,increasing in sliding speed induces an increase in wear rate and coefficient of friction. However,with further increasing in the sliding speed,the oxide film formed on the worn sufrace and the strain hardening of the surface layer contribute to decrease wear rate and coefficient of friction.