Microstructure, mechanical and tribological properties of A390/SiC composite produced by compocasting
(Department of Materials Engineering, Babol Noshirvani University of Technology, Shariati Avenue, Babol 47148-71167, Iran)
Abstract: Aluminum A390 alloys reinforced with 10 wt.% SiC composite, were produced by the compocasting method. The effects of temperature, time, and stirring speed of this compocasting method on the microstructure, mechanical and tribological properties of composite were investigated. The results indicated that with increasing the rotational speed from 450 to 550 r/min, the distribution of the SiC particles becomes more uniform. A sudden increase in porosity due to gas absorption results in a downtrend of elongation with an increase in stirring speed from 550 to 650 r/min. Furthermore, as the stirring time increases, the amount of agglomerates of primary Si particles is reduced, and a more uniform microstructure of SiC and Si particles is formed. Although the fracture mode is a combination of both brittle and ductile fractures, the main mechanism of the fracture in the compocast sample is ductile. The formation of a protective layer at a high temperature can result in a very low wear rate as compared to a wear test performed at a low temperature. Optimal particle uniformity and mechanical properties were obtained at processing parameters of 610 °C, 550 r/min, and 20 min.
Key words: A390/SiC compocasting; composite; microstructure; SiC particles