ABRASIVE WEAR CHARACTERISTICS OF ZN-37.2AL-2.5CU-0.2MG ALLOY DISPERSED WITH SILICON-CARBIDE PARTICLES

Observations made during two-body (high stress) abrasion tests conduct ed on a zinc-aluminium alloy reinforced with SiC particles have been r eported in this investigation. The matrix alloy, processed under ident ical conditions, was similarly studied in order to understand the resp onse of the reinforced second phase particles (SPPs), i.e. SiC, on the behaviour of the former. The influence of load and abrasive (SiC) siz e on the abrasion rate of the specimens was also studied. The study in dicates that the presence of the SPPs (in the matrix) reduced the abra sion rate of the matrix when abraded against fine abrasive particles b y providing protection to the matrix. However, the trend reversed when coarser abrasive was used. This was also evident from practically no damage to the SPPs (on the abraded surface) by the fine abrasive parti cles and substantial microcracking and fracturing of the SiC (abrasive as well as the SPPs) when coarser abrasive was used. Material removal mechanisms in the composite were observed to comprise the simultaneou s exposure of the matrix and the reinforced SPPs followed by microcrac king, fracturing and removal of the latter along with the matrix. The abrasive particles also were damaged during the process whose extent d epended on the abrasive size and load. The observations have been expl ained with the help of the analyses of the wear surfaces, subsurfaces, debris and the abrasive particles.