Study of Wear, Aging and Corrosion Behaviour of Aluminium-3%Magnesium-10%Silicon Carbide Composite

Abstract

Aluminium based metal matrix composites (MMCs) offer potential for advanced structural applications when high specific strength and modulus, as well as good elevated temperature resistance along with light weight and for marine applications. In the present work, aluminium-magnesium-silicon carbide composite (Al-3%Mg-10%SiC) developed using a stir casting technique is studied for wear, aging and corrosion behaviour. The wear behaviour of the composite is investigated at room conditions at four different loads, 70N, 80N, 90N, 100N and with varying sliding speeds, i.e.200, 300, 400, 500, 600, 700 rpm's, using a pin-on-disk wear testing machine. Then the composite was solution treated at a temperature of 250 C for 1hr and then aged at four different temperatures viz. 120 C, 150 C, 180 C, and 220 C to study the aging behaviour of the composite. The composite is kept in sea water for 42 days and the weight loss was measured in every 7 days to study the corrosion behaviour. Variation of cumulative mass loss with the applied load, sliding speed, sliding distance and friction co-efficient was studied from the pin-on-disk experiment. Micro structural characterization of the surfaces, micro-hardness measurement, and surface roughness studies of the worn surface are also made. The aging and corrosion mechanism is established with the aid of XRD analysis and scanning electron microscopy. It is found that, addition of silicon carbide to the Al-Mg matrix composite improves the wear resistance and hardness. Also, ageing process further improves the wear resistance and hardness. The dominant corrosion mechanism is found to be by pitting corrosion phenomena