Effect of B ₄ C Particles on Dry Sliding Wear Behavior of LM-13 Metal Matrix Composite

LM-13 aluminum alloys reinforced with B₄C particles (5, 10, 15 wt. %) were prepared by gravity die casting. The samples were characterized on the basis of microstructure, microhardness, XRD and SEM. The microhardness tests indicated increased hardness values of the metal matrix composite (MMC) as B₄C percentage increased. Optical microscopic observation revealed presence of rhomboidal hard B₄C particles distributed randomly in the LM-13 matrix. Presence of B₄C was also confirmed with XRD Analysis. The dry sliding wear behavior of this LM-13 - B₄C composite was investigated by means of the pin-on-disc technique. The results showed that as the B₄C % increased, the volumetric wear decreased proportionately - indicating the active role of the B₄C particles in wear reduction. Study of the worn surfaces of the composite using the SEM suggests presence of adhesive and abrasive wear mechanisms with evidence of transfer films. The improvement in wear resistance points to the presence of hard B₄C particles which acts as a positive reinforcement in the LM-13 matrix. The wear and hardness results suggest that the material could be a suitable candidate for brakes disc/drum application in light automotive vehicles.