Production of SiC particle reinforced aluminium matrix based composites by mechanical alloy method and investigation of their wear behavior

In this work, Al alloy (Al-2014) based Metal Matrix Composites (MMC?s) reinforced with varying size and weight fraction of SiC particles have been produced by using a mechanical alloy method and their dry wear behaviour have been investigated. Powder mixtures, consisting of Al and the various amounts of SiC particles were prepared by mixing in a vertical ball mill for 1,5 and 3,5 hours at a rotational speed of 450 rpm. Then the cylindrical sipecimens were obtained by pressing these powder mixtures in a die at 650 MPa pressure. The produced samples were sintered at 600 ºC for 2 hours in a pipe type of sintering furnace under a control of argon gas. Optical microscopic examination, hardness, density and porosity measurements were carried out. In addition, wear tests were performed in a pin-on-disc type of wear machine under different loads at a fixed speed. Furthermore, scanning electron microscope (SEM) and energy dispersive X-ray (EDAX) analysis were used to characterize the worn surfaces of composites. The density measurement showed that the samples contained a little porosity, and the amount of porosity in the composites increased with increasing volume fraction and decreasing size of particles. Optical microscopic observation of the microstructures revealed that the dispersion of the coarser sizes of particles was more uniform while finer particles led to agglomeration of the particles and porosity. In addition, the vii experimental results indicated that weight loss increased with decreasing particle size. However, the weight loss also decreased significantly with increasing SiC content in the composite due to its hardness. Moreover, the wear rates of all samples increased with increasing loads at all wear tests. Furthermore, SEM examination showed that the wear mehanism was oxidation and plastic deformation under higher load conditions, but oxidation and crater were dominant under lower testing conditions.