Abrasive wear characteristics of Zn-37.2Al-2.5Cu-0.2Mg alloy dispersed with silicon carbide particles

Abstract

Observations made during two-body (high stress) abrasion tests conducted on a zinc-aluminum alloy reinforced with SiC particles have been reported in this investigation. The matrix alloy, processed under identical conditions, was similarly studied in order to understand the response of the reinforced second phase particles (SPPs), i.e. SiC, on the behaviour of the former. The influence of load and abrasive (SiC) size on the abrasion rate of the specimens was also studied. The study indicates that the presence of the SPPs (in the matrix) reduced the abrasion rate of the matrix when abraded against fine abrasive particles by 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 particles 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 simultaneous exposure of the matrix and the reinforced SPPs followed by microcracking, fracturing and removal of the latter along with the matrix. The abrasive particles also were damaged during the process whose extent depended on the abrasive size and load. The observations have been explained with the help of the analyses of the wear surfaces, subsurfaces, debris and the abrasive particles.