Wear properties of copper-coated short steel fiber reinforced stir cast Al–2Mg alloy composites

Abstract

In the present investigation, wear properties on 2.5, 5 and 10 wt% copper-coated short steel fiber reinforced Al–2Mg alloy composites fabricated by stir casting process were carried out using pin-on-disc wear testing apparatus. The effects of sliding distance, applied load and wt% of fiber on the dry sliding behaviour were evaluated. Dry sliding wear tests at room temperature revealed that the wear rate of MMCs were significantly lower than alloy. The coefficient of friction and the wear rate also decreased with increasing fiber content. The worn surface and debris of specimens were examined under scanning electron microscopy (SEM) to find out the wear mechanism. SEM observations revealed that extensive microcracks occur on the surface of the alloy tested at lower loads. The growth of these microcracks eventually led to the delamination of debris from the alloy surface. The copper-coated steel fiber addition tended to reduce the plastic deformation in the surface layer there by reducing the occurrence of microcracking in the MMCs. The wear mechanisms of MMCs are dominated by oxidative wear at lower load but it changed to severe wear when applied load are increased. The composites containing 2.5 and 5 wt% of fibers exhibited a load dependent transition from mild to severe wear with increasing load. In case of 10-wt% fiber composites showed only mild wear even at higher applied load.