Wear and friction behavior of stir cast aluminium-base short steel fiber reinforced composites

The wear and friction behavior of aluminium matrix composites reinforced with short steel fibers has been investigated. The metal matrix composites were fabricated by liquid process using vortex method with commercially pure Al matrix reinforced with short plain steel fibers, copper-coated and nickel-coated steel fibers. A pin on disc type apparatus was employed for determining the sliding wear rate and the coefficient of friction. The applied load was varied in the range of 10–40 N. The study reports the effects of applied load and coating on the dry sliding wear rate and coefficient of friction of the composites. Addition of fibers reduced the wear rate considerably at all applied loads. The volumetric wear increased with increasing applied load. The wear mechanism was studied with scanning electron microscope. Oxidative wear was predominant at lower loads. With increasing load the dominant wear mechanism changed to delamination and subsurface cracking assisted adhesive wear. On the basis of microscopic observations and analysis of the wear surface, the wear debris and coefficient of friction a change in mode of wear from mild to severe was noted at varying loads depending on the percentage reinforcement present. The transition from mild wear to severe wear depends on the strength of the pin material adjacent to the contact surface and the strain induced shear stress created by applied loads.