Wear 258 (2005) 759–767 Wear and friction behavior of spray formed and stir cast Al–2Mg–11TiO 2 composites S.K. Chaudhury a,* , A.K. Singh a , C.S. Sivaramakrishnan a , S.C. Panigrahi b a MTP Division, National Metallurgical Laboratory, P.O-Burmamines, Jamshedpur – 831007, India b Department of Metallurgical and Materials Engineering, I.I.T.-Kharagpur, West Bengal – 721302, India Received 6 October 2003; received in revised form 9 August 2004 Available online 14 October 2004 Abstract In present studies, the frictional and wear behavior of Al–2Mg–11TiO 2 composites prepared through spray forming and stir casting techniques are studied. For the comparative purpose, the spray formed base alloy (Al–2Mg) is also tested under same sliding condition. The paper documents our findings on various wear characteristics of both composites and base alloy tested under the same range of sliding distance at various normal loads. The wear rate of spray formed composites is significantly lower than the base alloy and stir cast composite under same sliding condition. Further, a change in wear mechanism from consistently adhesive type in alloy to a mixed mode of oxidative–abrasive wear in composites is noted. A decrease in coefficient of friction in composites vis-` a-vis matrix alloy is also observed. © 2004 Elsevier B.V. All rights reserved. Keywords: Wear; Friction; Composites 1. Introduction The critical need for lightweight and high performance materials (in the areas of automotive, aerospace, deep ocean, nuclear energy generation and other structural applications) and limitations of conventional monolithic metals and al- loys with regard to combination of properties (namely spe- cific strength, stiffness, wear rate) [1–4], have led to the development of hybrid materials in the form of compos- ites. The last two decades have witnessed extensive research work in this direction and have shown tremendous promise and phenomenal growth of composites. Aluminium based metal matrix composites are the materials of recent interest for structural applications owing to their superior properties, such as high specific modulus specifically at high tempera- tures, good strength and low wear rates, vis-` a-vis monolithic alloys [3,4]. * Corresponding author. Present address: 100 Institute Road, WPI, MPI, Worcester, MA-01609, USA. Tel.: +1 508 831 6503; fax: +1 508 831 5993. E-mail address: sujoy@wpi.edu (S.K. Chaudhury). With the increasing demand for lightweight, energy effi- cient materials, light metal matrix composites are bound to find many applications, provided they meet specific friction and wear requirements, while maintaining reasonable me- chanical properties. Wear of a material is controlled by the material characteristics as well as test parameters such as applied pressure, sliding speed, environment and the type of sliding interaction. Wear behavior in metal matrix composites (MMCs) can be divided into two categories depending upon the nature of reinforcements. These are metal/alloys contain- ing: (1) soft reinforcements like graphite, (2) hard particles like SiC, Al 2 O 3 , TiO 2 , etc. The presence of hard particles also influences the wear be- havior. The use of hard ceramic particles like Al 2 O 3 , SiC, etc. as reinforcements in the metallic matrix have shown [6] to re- duce the wear loss as compared to the base alloys. In general, it has been observed [5–7] that the wear rate decreases both by increase in hard phase volume fraction and particles size. Fur- ther, the use of hard phase helps in pushing the seizure on the higher load at constant sliding velocity. In a study [6], it was observed that the wear rate of Al 2 O 3 reinforced composites 0043-1648/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.wear.2004.09.007