Journal of Materials Processing Technology 211 (2011) 1423–1431 Contents lists available at ScienceDirect Journal of Materials Processing Technology journal homepage: www.elsevier.com/locate/jmatprotec Abrasive wear behavior of Ni–P coated Si 3 N 4 reinforced Al6061 composites C.S. Ramesh ∗ , R. Keshavamurthy, S. Pramod, Praveennath G. Koppad Department of Mechanical Engineering, PES Institute of Technology, Bangalore 560085, India article info Article history: Received 12 October 2010 Received in revised form 14 March 2011 Accepted 15 March 2011 Available online 23 March 2011 Keywords: Al6061 Coating Silicon nitride Abrasive wear abstract Ni–P coated Si 3 N 4 reinforced Al6061 composites were fabricated by vortex method. Percentage of rein- forcement was varied from 6 wt.% to 10 wt.% in steps of 2. Cast matrix alloy and developed composites were hot forged at a temperature of 500 ◦ C using a 300T hydraulic hammer. Both as cast and hot forged matrix alloy and its composites were subjected to microstructure studies, grain size analysis, micro- hardness and abrasive wear tests. Microstructure studies reveal uniform distribution of silicon nitride particles with good bond between matrix and reinforcement in both as cast and hot forged condition. It is observed that, increased content of reinforcement in both as cast and hot forged composites do result in significant grain refinement. However, when compared with as cast matrix alloy and its com- posites hot forged alloy and its composites exhibits higher extent of grain refinement. Both as cast and hot forged composites exhibit improved microhardness and abrasive wear resistance when compared with the unreinforced alloys under identical test conditions. Abraded worn surfaces were examined using scanning electron microscopy (SEM) for possible wear mechanisms. Increased abrasive particle size and load has resulted in larger extent of grooving leading to increased abrasive wear loss for both the matrix alloy and developed composites. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Discontinuously reinforced aluminum matrix composites (DRAMCs) have been of interest as engineering materials because of their improved strength, stiffness and superior wear resistance when compared with their unreinforced alloys (Han et al., 1999). Potential application of DRAMCs in automobile sector includes components like piston cylinder liner brake drums, crankshafts, etc. (Vencl et al., 2004). Many of these components do undergo sliding as well as abrasive type of wear during operation. In view of this considerable attentions have been paid to investigate the sliding and abrasive wear behavior of aluminum based composites under various test conditions. Singh et al. (2006) have reported on abrasive wear behavior of aluminum alloy/silimanite particle reinforced composites under low stress condition. They have observed that wear resistance of the composite was higher than the matrix alloy under all the stud- ied test conditions. Sanjeev Das et al. (2007) have carried out a comparative study on abrasive wear behavior of aluminum com- posite reinforced with alumina and zircon sand particles. They have noticed that, wear resistance of the aluminum alloy improved sig- nificantly after addition of alumina and zircon particles. Decrease ∗ Corresponding author at: PES Institute of Technology, Mechanical Engineering, 100ft Ring Road, BSK 3rd Stage, Bangalore, Karnataka 560085, India. Tel.: +91 80 2672 1983; fax: +91 80 2672 0886. E-mail address: csr gce@yahoo.co.in (C.S. Ramesh). in reinforced particle size improved the abrasive wear resistance for both alumina and zircon. Zircon reinforced composite shows better wear resistance than alumina reinforced composite due to its superior particle–matrix bonding. DRAMCs composites are primarily synthesized by various tech- niques (Ramesh and Safiulla, 2007) such as powder metallurgy, vortex method, and infiltration technique, squeeze casting, etc. Among all these, vortex method is one of the most popular meth- ods, in view of its simplicity, easy adaptability, mass production and applicability to large quantity production. However, due to limita- tions like, non uniform distribution of reinforced phase, absence of sound interface between matrix and reinforcement, and presence of inherent casting defects like porosities, composites prepared by this technique cannot be used directly for specific applications. It has been well proven that secondary processing of DRAMCs can lead to reduction or elimination of porosity, improved bond between matrix and reinforcement and uniform distribution of the reinforced particles. These factors do contribute to significant improvement in mechanical and tribological properties of primar- ily processed composites (Durrant and Scott, 1993). Ozdemir et al. (2000) have studied the hot forging behavior of aluminum compos- ites reinforced with silicon carbide particles. They have obtained significant improvement in strength and ductility of the developed composites. Harrigan et al. (1983) have reported on mechanical properties of hot rolled Al6061-SiCp composites. The applications of hot rolling process have improved the particulate distribution, strength and ductility of composites. Umit Cocen and Kazim onel (2002) have studied the effect of hot extrusion on strength and 0924-0136/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2011.03.015