Abrasive wear behaviour of SiCp/Al alloy composite in comparison with ausferritic ductile iron

The abrasive wear behaviour of SiCp/Al composites (MMCs) prepared by liquid metallurgy method was investigated to find out effects of applied load and weight fraction on a pin-on-disc configuration. The MMC pins containing 20 wt.% particles with sizes of 50 μm and its 2014 Al alloy were tested under different conditions against SiC abrasives. The wear performances of MMCs were also compared with those of ductile iron (DI), partially austenitized and austempered ductile iron (PADI) and conventionally austenitized (full austenitized) and austempered ductile iron (CADI) under similar conditions. Moreover, wear surfaces of tested samples were examined in a scanning electron microscope (SEM). Hardness, density and porosity increased with increasing wt.% of particle for the composite, but for the PADI and CADI sample, hardness increased with increasing martensite volume fraction and ausferrite volume fraction. The experimental results showed that wear rate of the composite decreased slightly with increasing SiCp contents and increased with increasing load. The wear resistance of MMCs was found to be better then those of DI, PADI and CADI materials, when tested against 70 μm sizes of abrasives. Furthermore, SEM examination showed that a few wear craters, combined with re-attachment of debris particles, was dominant for the composite, but the fragmented debris particles, when tested at lower loads, were found the more dominant for MMCs. Adhesion, chipping and abrasion were responsible mechanisms for the alloy, but abrasion was the most effective mechanism for the CADI samples.

► The applications of SiC/Al composites have been increased in the aerospace, automobiles industry for structural materials while partially austenite ductile irons (PADI's) have been found to be validated for suspension parts of the automotive. A comparison is made between MMCs and DI’ based materials in terms of abrasive wear behaviour at different conditions.
► It is found that the wear resistance of MMCs was found to be better than those of DI based materials when tested against 70 μm size of abrasive. It meant that the selection of the composites became a very favourable when such an abrasive was used.
► SEM examination showed that the fragmented debris particles were more effective for the MMCs while adhesion, chipping and abrasion were responsible mechanisms for the base alloy, but abrasion was the effective mechanism for the CADI's.