Structure and properties of short alumina fibre reinforced AlSi18CuNi produced by stir casting

摘要

In this study, AlSi18CuNi-based metal matrix composites (MMCs) containing up to 12 wt. percent of alumina short fibres were successfully synthesized using casting route. The structure of the produced composites and matrix alloy was examined using optical microscopy. At the same time, specimens from these alloys were machined and used for mechanical and wear tests. The results revealed that Al_2O_3 fibres refined the structure of AlSi18CuNi alloy. Also, metallography of the composites showed that the Al_2O_3 fibres were essentially uniformly distributed throughout the matrix. At the same time, the results showed that the mechanical properties and wear resistance of the as cast alloys were improved by the additions of alumina fibres. The composites showed an increase in tensile strength and hardness at ambient temperature over that of the matrix alloy. On the other hand, a decrease in tensile properties at elevated temperature of both matrix and composite alloys was noticed, but still the composites showed higher values compared with the matrix alloy. Pin on ring dry sliding test was carried out to study wear behaviour of the prepared alloys. Higher wear resistance was observed for the composites compared to the unreinforced alloy.