Friction and wear behavior of laser-sintered iron-silicon carbide composites

Laser sintering is currently one of the most popular techniques to develop innovative materials for many of the high tech industrial applications owing to its ability to build complex parts in a short time. As such, material researchers are focusing on developing advanced metal matrix composites through selective laser sintering method to develop an intricate component eliminating delay in production time. In the light of the above, the present work focuses on developing iron-silicon carbide (nickel coated) composites using direct metal laser sintering technology. A laser speed of 50, 75, 100 and 125 mm/s were adopted. Metallographic studies, friction and wear test using pin-on-disc have been carried out on both the matrix metal and its composites. Load was varied from 10 to 80 N while sliding velocity was varied from 0.42 to 3.36 m/s for a duration of 30 min. A maximum of 7 wt.% of silicon carbide has been successfully dispersed in iron matrix by laser sintering. Increased content of SiC in iron matrix has resulted in significant improvement of both hardness and wear resistance. Lower the sintering speed, higher is the hardness and wear resistance of both the matrix metal and its composites. However, coefficient of friction of composites increased with increased SiC under identical test conditions. SEM observations of the worn surfaces have revealed extensive damage to the iron pins, when compared with that of the composites. (C) 2009 Elsevier B.V. All rights reserved.