Wear 249 (2001) 656–662 Influence of Ti addition on wear properties of Al–Si eutectic alloys N. Saheb a,∗ , T. Laoui b , A.R. Daud a , M. Harun c , S. Radiman a , R. Yahaya a a School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia b Department of Metallurgy & Materials Engineering, University of Leuven, K.U. Leuven, Belgium c Malaysian Institute for Nuclear Technology Research, Bangi 43000 Kajang, Malaysia Received 3 January 2001; received in revised form 2 May 2001; accepted 10 May 2001 Abstract The influence of Ti addition (up to 4 wt.%) on wear behavior of as-cast and heat-treated Al–12 wt.% Si eutectic alloy prepared by rapid cooling has been investigated in dry sliding against a steel counterface using a pin-on-disk apparatus. Worn surfaces and wear debris were examined and analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The addition of Ti to the binary Al–Si alloy led to the precipitation of Al 3 Ti phase. Among the Ti-containing alloys, the increase in Ti content improved wear resistance of both as-cast and heat-treated alloys. However, these alloys displayed higher wear rates, thus lower wear resistance, compared with the Al–Si binary alloy. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Al–Si–Ti alloys; Wear debris; Wear rate; Dry sliding 1. Introduction Al–Si alloy is a well-known casting alloy with high wear resistance, low thermal-expansion coefficient, good corrosion resistance, and improved mechanical properties at a wide range of temperatures. These properties led to the application of Al–Si alloys in the automotive industry, especially for cylinder blocks, cylinder heads, pistons, and valve lifters [1]. Wear properties of these alloys have been studied mainly under dry sliding conditions against a steel counterface. Previous studies include the effect of silicon content in the alloys on mild wear [2–5], mechanics of mild wear in hypoeutectic alloys [2,3,6–9] and hypereutectic alloys [6], and construction of wear maps of Al–Si alloys [10,11]. It has been reported that the addition of silicon to pure aluminum improves wear and seizure resistance [12]. Torabian et al. [13] have shown that the hardness of Al–Si alloys increases with increasing Si content, and un- der specific conditions of constant applied load and sliding velocity, the wear rate decreases as well. Several authors have investigated the influence of vari- ous alloying elements on wear resistance of Al–Si alloys [14–18]. The addition of 2 wt.% Ti to the rapidly solidified Al–20 wt.% Si–5 wt.% Fe alloy was reported to increase its wear resistance and mechanical properties, while V addition was less effective than Ti [14]. The addition of ∗ Corresponding author. Tel.: +603-8929-3806; fax: +603-8929-2415. E-mail address: p13088@mail2.ukm.my (N. Saheb). 1.5 wt.% Cu to rapidly solidified and processed Al–Si base alloys improved the wear behavior at high loads due to the precipitation of a hard-phase Al 2 Cu, which inhibits further wear in these alloys [15]. Lead content from 2 to 10 wt.% in Al–Si–Pb alloys has been found to decrease the wear rate and increase the load-bearing capacity of the alloys [16]. A lower friction coefficient and a higher seizure load were obtained for Al–Si–Pb alloys bearing in semi-dry sliding conditions compared with those observed for dry conditions, and the addition of lead is generally found to reduce inter- facial friction and improve the ability to resist seizure [17]. The wear characteristics of binary Al–Si alloys and a com- mercial LM 13 alloy have been reported elsewhere [18]. It was shown that the addition of cerium, zinc, and zirconium as well as subsequent heat treatment significantly improved wear resistance of the alloys. The aim of the present work is to investigate the influence of Ti addition on wear properties of as-cast and heat-treated Al–Si eutectic alloy in dry sliding against a steel counterface by using pin-on-disk wear tests. 2. Experimental methods High purity elements, aluminum (99.9 wt.% purity), sili- con (99.95 wt.% purity), and titanium (99.99 wt.% purity) were melted in a graphite crucible at 1400 ◦ C for 30 min under argon gas atmosphere in a high-temperature pro- grammable furnace (Nabertherm, model LHT 02/18). The 0043-1648/01/$ – see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0043-1648(01)00687-1