An investigation of the effect of work piece reinforcing percentage on the machinability of Al-SiC metal matrix composites

Abstract

This paper presents the study of the tool wear mechanism in machining the metal matrix composites (MMC) and its dependence on the percentage of reinforcing with MMC. Aluminum alloy (A356 - SiC) silicon carbide metal matrix composite of two samples, were prepared in-house by using stir casting method. Samples having 10 and 20% silicon carbide particles (grain size ranging from 55 to 85 mm) by weight are fabricated in the form of cylindrical bars. Experiments were conducted in the medium duty lathe by using polycrystalline diamond (PCD) insert. Optimum parameters were obtained by analyzing the power consumed on an average surface roughness (Ra) of the machined component. By setting these optimum parameters at a constant machining condition, tool wear study was carried out for a time duration of 100 min. The result showed that the tool flank wears was maximum while machining 20% of the SiC reinforcing MMC when compared with 10% of the SiC reinforcing MMC. The result proved that the influence of SiC particles’ weight percentage was a dependent parameter on tool wear. The main mechanism of tool wear in machining Al-SiC MMC includes two-body abrasion and three-body abrasion. However, the tool wear images were captured by optical microscope and SEM, which supported the result. Key words: Machining, PCD, Al-SiC-MMC, different percentage of SiC reinforcing, power consumed, tool wear.