Effect of abrasive size on wear of metallic materials and its relationship with microchips morphology and wear micromechanisms: Part 2

In this paper, the effect of abrasive particle size on the wear of three different metallic materials (AISI 1045 steel, aluminum alloy and gray cast iron) was investigated. Abrasive wear tests using a pin on alumina paper were carried out using abrasive sizes between 16 mu m and 192 mu m. The wear surface of the specimens was examined by SEM for identifying the wear micromechanism and the type of microchips (wear debris) formed on the abrasive paper. The results show that the mass loss for the AISI 1045 steel and for the aluminum alloy increases linearly with the increase of particle size until the critical particle size is reached. After the critical particle size is reached, the rate of mass loss of the aluminum alloy increases at a lower linear rate, and for the AlS11045 steel the curve of mass loss is non-linear and flattens when the critical particle size is reached. The abrasive paper in contact with the AlS11045 steel presents continuous microchips before reaching the critical particle size (about 116 mu m) and after it, it presents deformed discontinuous microchips and abrasive fracture. The abrasive paper in contact with aluminum presents clogging and continuous microchips before the critical particle size (about 36 mu m) and after it, it presents discontinuous microchips. The wear surfaces of the AISI 1045 steel and the aluminum alloy present microcutting as the main wear mechanism before reaching critical particle size, and after that, it presents microploughing as the main wear mechanism. The gray cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the microchips was similar for the different sizes of abrasive (discontinuous). However, at smaller abrasive sizes, some thin continuous microchips and clogging were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. The results show that the effect of critical abrasive size on wear in metallic materials can be related with the wear micromechanisms and the microchips morphology. (C) 2011 Elsevier B.V. All rights reserved.