DRY SLIDING WEAR BEHAVIOR OF ULTRAFINE GRAINED COMMERCIAL PURITY ALUMINUM AND LOW CARBON STEEL PRODUCED BY SEVERE PLASTIC DEFORMATION TECHNIQUES

Abstract

Dry sliding wear behavior of ultrafine grained commercial purity aluminum (1100) and low carbon steel (Fe-0.15%C-0.25%Si-1.1%Mn) was investigated. Ultrafine grains of the aluminum and the steel were obtained by an accumulative roll bonding (ARB) process and equal channel angular processing (ECAP), respectively. A remarkable enhancement in hardness, tensile and yield strength was achieved by the severe plastic deformation techniques. However, little strain hardening was observed in both ultrafine grained materials. Pin-on-disk wear tests of the ultrafine grained materials were carried out under various applied load and sliding speed conditions at room temperature. Sliding wear of the materials proceeded by surface deformation. In spite of the increased hardness and strength, wear resistance of the ultrafine grained materials was lower than that of the large grained as-received ones. Decreasing wear resistance with increase of the number of ARB cycle was also observed under the present test conditions. The low wear resistance of the ultrafine grained materials was attributed to their low strain hardening capability. Recovery and smoothed grain boundaries resulting from the increase of accumulative strain were also postulated as causes for the decreasing wear resistance.