Experimental investigation of the effect of insert spacing on abrasion wear resistance of a composite

Reducing abrasive wear is crucial to minimising economic losses in bulk solids handling, particularly in the mining industry. The present study investigates the wear behaviour of macro-scale composites, consisting of hard inserts equi-spaced in a soft matrix, with a length-scale comparable to the size of abrasive particles. The experiments explored the effect of insert spacing on the formation of protective particle layers to reduce wear. Hardened tool steel inserts were embedded in a soft aluminium matrix. The spacing between inserts decreased with increasing volume fraction of inserts (8, 23 and 40 vol%). An instrumented dry sand rubber wheel test was used to conduct accelerated wear tests, and to measure the thickness of the protective abrasive particle layer formed during the tests. The soft aluminium matrix wore preferentially, leaving the tool steel inserts standing proud. The exposure height of the inserts reached a steady state for extended wear stages. Interestingly, the composites with 23 and 40 vol% of inserts showed significantly less wear than predicted by the rule of mixture. When the insert spacing was equal to the abrasive particle size, the thickness of the abrasive particle layer was larger than for specimens without inserts. This study reveals that the spacing between the inserts, with respect to the abrasive particle size, is an important design parameter for the development of enhanced wear resistant composites.