FACTORS CONTROLLING THE ABRASIVE WEAR RESPONSE OF A ZINC-BASED ALLOY SILICON-CARBIDE PARTICLE COMPOSITE

Attention has been focused in this study on the (two-body/high-stress) abrasion characteristics of a zinc-based alloy reinforced with hard S IC second phase particles (SPPs) under the influence of varying load, sliding distance and abrasive size. The unreinforced matrix alloy proc essed similarly was also subjected to identical test conditions. It wa s observed that the wear response of the specimens is influenced marke dly by the applied load, sliding distance and the size of the abrasive particles. Different operative wear mechanisms were found to be respo nsible for the changing behaviour of the samples. Reinforcement with h ard SPPs (SIG) in the zinc-based alloy matrix was beneficial when test s were conducted with fine abrasive particles over the entire range of applied loads and sliding distance. On the contrary, however, this tr end reversed when coarser abrasive particles were used. Further, the w ear rate reduced with sliding distance, while load affected the wear b ehaviour of the specimens in the opposite manner. These effects, of co urse, were more prominent under severe conditions of abrasion (i.e. hi gher load or coarser abrasive). The wear characteristics of the sample s have been explained on the basis of factors such as degradation of t he abrasive, as well as reinforcing SPP and abrasion-induced work hard ening of the subsurface regions. In addition, the predominance of one or more processes such as capping, clogging, shelling and attrition, l eading to a deteriorating cutting efficiency of the abrasive and britt le fragmentation of the SPPs, affected the wear response of the specim ens markedly under a given set of experimental conditions. (C) 1997 El sevier Science Limited.