Wear of Al–Si alloys matrix reinforced with sol–gel coated particles

Abstract

In the present study, squeeze cast A356 matrix composites reinforced with coated B4C particles were fabricated. Attempts were made to coat the B4C powders with TiB2 via a sol–gel process and incorporate them into the A356 alloy by a mechanical stirrer. The hardness of B4C particle is the third highest among all materials of this type. The wear properties of unreinforced A356 alloy and composites with different volume percentages of coated boron carbide particles were experimentally investigated. It is noted that composites exhibit better wear resistance compared to unreinforced alloy. The presence of B4C particles could shield the matrix and silicon phases from directly experiencing the applied load and reduce the weight loss during the wear test. According to the differences in wear rates of the composites, two separate wear rate regimes were identified as low and high wear rate regimes. Microscopic examination by a scanning electron microscope equipped with an energy dispersive spectrometer has also been carried out on the worn surfaces and debris.