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An examination of microstructure, mechanical and dry wear properties of stir cast brass/Al2O3 composites

ABSTRACT Brass/Al2O3 composites, containing 0–6 wt-% of alumina, were prepared, for the first time, by stir casting. The microstructure, density, hardness, compressive strength and wear behaviour of resulted composites were studied. The coarse grains in the unreinforced specimen became finer needle-like structure in the composites. Alumina particles added to the melt can be effective in encouraging pore formation and reducing the density of composite specimens. Results showed that the highest hardness and yield strength, with respectively 63% and 136% increase, were related to the composite containing 4 wt-% of reinforcement. Furthermore, the maximum wear resistance was obtained in this composite. Wear volume and wear rate approximately decreased by 46% and 48.5% for 20 N of applied load, respectively. The addition of the second phase particles and the increase in applied load resulted in a reduction of friction coefficient. Adhesive, abrasive and delamination wear were identified as the main wear mechanisms.