Wear 267 (2009) 1777–1783 Contents lists available at ScienceDirect Wear journal homepage: www.elsevier.com/locate/wear Abrasive wear behaviour of laser sintered iron–SiC composites C.S. Ramesh a,∗ , C.K. Srinivas b , B.H. Channabasappa c a Mechanical Engineering, PES Institute of Technology, BSK III Stage, Bangalore 560 085, India b Central Manufacturing Technology Institute, Tumkur Road, Bangalore 560 022, India c PES Institute of Technology, BSK III Stage, Bangalore 560 085, India article info Article history: Received 18 September 2008 Received in revised form 29 December 2008 Accepted 31 December 2008 Available online 24 January 2009 Keywords: Direct metal laser sintering Abrasive wear Metal matrix composite Rapid prototyping abstract Direct metal laser sintering (DMLS) is one of the popular rapid prototyping technologies for produc- ing metal prototypes and tooling of complex geometry in a short time. However, processing of metal matrix composites (MMCs) by laser sintering is still in infant stage. Thermal cracks and de-bonding of reinforcements are reported while processing MMCs by laser sintering process. There are reports on use of metallic-coated ceramic reinforcements to overcome these problems. The present investigation is aimed at using nickel-coated SiC in developing iron composites by DMLS technique and to characterize its abrasive wear behaviour. Microstructure, microhardness, and abrasive wear tests have been carried out on both DMLS iron and its composites sintered at a laser scan speed of 100 mm/s. Abrasion wear tests have been carried out using a pin-on-disc type machine. SiC abrasive papers of grit size 60, 80, and 150 having an average particle size of 268, 192, and 93 m, respectively, have been used. Load was varied between 5 and 25N in steps of 5, while the sliding distance and sliding velocity of 540 m and 2.5 m/s, respectively was adopted for all the tests. Optical, scanning electron micrograph and surface roughness observation of worn surfaces have been undertaken. An increase in microhardness and a decrease in density of the laser sintered iron–SiC composites was observed with increase in SiC content. The abrasive wear resistance of composites increases with increased content of SiC in iron matrix. For a given grit size of SiC abrasive paper, at all the loads studied, iron–SiC composites exhibit excellent abrasive wear resistance. Increase in abrasive wear was observed with the increase in abrasive particle size. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Wear can be defined as the gradual removal of material from solid surfaces as a result of mechanical action. Abrasive wear accounts for 50% of wear encountered in industrial situations [1]. Abrasive wear occurs when hard rough surface slides against a soft surface thereby removing material in the form of elongated chips. It is well accepted that abrasive wear rate of a surface is inversely proportional to its hardness [2]. Metal matrix compos- ites (MMCs) which are currently the most sought after materials have excellent mechanical properties such as high strength, stiff- ness and hardness when compared with the matrix alloy. They have a potential for increased wear resistance over the unreinforced alloy. Das et al. have performed abrasive wear test on Al–Si alloy and its composite with SiC as reinforcement. It is reported that the composite has better wear resistance when compared with Al–Si alloy [3]. Gurcan et al. have conducted abrasive wear test ∗ Corresponding author. Tel.: +91 80 26720886. E-mail address: csr gce@yahoo.co.in (C.S. Ramesh). of AA6061 aluminium and its composite reinforced with SiC. It is reported that composite containing 60% SiC has a wear rate five times lower than the 20% SiC composite [4]. Sahin has performed abrasive wear test on Al-2014 and its composite having 10 wt.% SiC. It is reported that there was an improvement in the wear resistance of composites compared with matrix alloy. Further an increase in applied load has resulted in increase in wear rate [5]. Deuis et al. in their review paper on abrasive wear of aluminium composites have reported that increasing the volume fraction of reinforcing phase has resulted in improved wear resistance of composites. Fur- ther, wear increases with the increase in grit size up to a particular value beyond which the wear rate is independent of the abrasive grit size [6]. Sahin et al. have constructed a abrasive wear model for wear behaviour of aluminium-based composite and have found that wear rate of the composite increased with increase in applied load, abrasive size and decreased with sliding distance [7]. Tjong et al. have performed abrasive wear test on TiB 2 /Al–4 wt.% cop- per composites produced by isostatic pressing. It is reported that abrasive wear resistance of the composite increased with increas- ing TiB 2 content [8]. Development of MMCs by rapid prototyping technique is still in the infant stage. Few researchers have done 0043-1648/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.wear.2008.12.026