Abstract
Abstract
The current work focused on the influence of cooling rate on the microstructure, mechanical and tribological properties of cast in-situ composite. It was observed that the size of intermetallic phase Mn(Al1-xFex)6 and the dendrite arm spacing (DAS) increases considerably with decreasing cooling rate of the cast ingot. Microstructural examination of these different cast in-situ composites shows that there is no significant difference in the size of the in-situ formed alumina particle. Superior mechanical properties, as indicated by ultimate tensile stress, yield stress, percentage elongation and hardness, are obtained when the in-situ composites are processed by cooling the cast ingot in water, resulting in refined microstructure. Higher hardness due to refined microstructure and superior mechanical properties result in decreased wear rate in cast in-situ composites cooled in water after casting, compared to the wear rates observed in cast ingots cooled either in air or inside furnace. Cast in-situ composite cooled in water after casting, shows higher coefficient of friction compared to those cooled in air or inside furnace.
