DISCONTINUOUSLY REINFORCED ALUMINUM COMPOSITES SLIDING AGAINST STEEL - STUDY ON WEAR BEHAVIOR

The microstructural and technological characteristics of metal matrix composites can be tailored if the role played by typical reinforcement parameters (type, shape, and volume fraction) is correctly evaluated. The present work used commercially pure Al reinforced with ceramic pa rticles (Al2O3, SiC), manufactured via powder metallurgy and hot extru ded. The volume fraction of reinforcement ranged from 5 to 15%. Dry sl iding tests were performed on the composites using a flat on cylinder tribometer and the friction coefficient versus sliding distance was re corded. The counterface was a carbon steel cylinder treated up to a Ro ckwell hardness of 60 HRC. The microstructure of the worn surfaces of the composites was evaluated via light microscopy, scanning electron m icroscopy, and transmission electron microscopy. The wear behaviour an d microstructural evolution of all materials including the unreinforce d matrix, were related to both reinforcement variables and testing con ditions. Using wear mechanism mapping, some guidelines for designing a nd selecting wear resistant composites are suggested. (C) The Institut e of Materials.