Effect of Addition of TiC Master Alloy on the Properties of CK45 Mansour Razavi, Razieh Ghaderi, Mohammad Reza Rahimipour, and Mohsen Ostad Shabani Materials and Energy Research Center (MERC), Tehran, Iran In this article, the effect of addition of synthesized TiC nanocrystalline master alloy to CK45 steel on the microstructure, hardness, and wear resistance was investigated. Master alloy was synthesized from milling of ferrotitanium and carbon black in a planetary ball mill. After detecting of properties of synthesized materials, one type of master alloy has been selected and injected into molten steel in high frequency induction furnace. Studies showed that by adding the synthesized master alloy into molten steel, this phase was distributed more homoge- neously and caused to produce Fe-TiC composite with finer grains along with better mechanical properties and wear resistance than Ck45 steel. Keywords Ferrous; Milling; Nanocomposites; Nanocrystalline; Strength. INTRODUCTION Metal matrix composites (MMCs) are attractive materials to be employed in various applications because of their improved properties [1]. Although much of this interest is focused on the lighter structural metals such as Ti, Mg, and Al to attain improved strength and stiffness, there has been significant interest in developing particu- late iron-based MMCs owing to their excellent wear resistance, cutting performance with improved toughness, and significant cost reduction over existing materials, as tool material for machining purposes [2]. Ceramic particulates such as borides, carbides, and nitrides are added to the ferrous matrixes [3]. However, TiC with high hardness, good wettability, low density, and chemical stability is more common [2, 4]. Especially, TiC can be chemically wetted by iron matrix, and the wetting angle between TiC and molten iron alloy is less than 50  even in high temperature and many different kinds of atmosphere [5]. Thus, iron-based composites containing TiC have received particular attention, as early as the 1950s. These composites are currently available and marketed commercially under a number of trade names (for example, ferro TiC, TiCalloy and ferrotitanit) [4, 6–7]. They exhibit the toughness and machinability associated with conventional alloy steels combined with significant improvements in hardness and wear resistance. This composite is used in many applications where retention of mechanical properties at elevated temperature is important [8]. Gas and steam turbines, coal liquefaction and gasification processes, and aircraft engines are numerous potential applications for these materials [9]. Mainly two techniques are available to incorporate second phase particles in the matrix;. The first technique, solid state process, includes powder metallurgy, self- propagating high-temperature synthesis (SHS), mechan- ical alloying, and aluminothermic reduction. These routes generally suffer from the problems of porosity and contaminated matrix–reinforcement interfaces [2–3, 10–12]. The second technique is liquid state pro- cess. Preparation of composites by casting technique has the advantage of producing near net shaped pro- ducts [2, 4]. Addition of carbon into the Fe-Ti molten, addition of titanium metal chips or TiC powder into Fe-C molten, and mixing of Fe-Ti and Fe-C have been reported as the possible methods for production of Fe-TiC composite [4, 13–15]. Addition of TiC to molten iron or steel results in the iron binder melting which enables the particles of TiC to disperse throughout the host metal [6]. In view of the above and pursuant to the authors’ pervious article [16], in this research article, after brief description about synthesis of TiC master alloy by mechanical alloying, an attempt has been made to study the effect of addition of this master alloy to molten of CK45 steel. EXPERIMENTAL In this article, master alloy of titanium carbide was produced by mechanical milling. Details of synthesized process were presented in the authors’ pervious article [16]. After investigation of properties of synthesized material regarding the above stage, the appropriate com- pound was selected and added to the molten of CK45 steel with chemical composition as given in Table 1. Employed furnace for casting was high frequency induc- tion type with frequency of 1 MHz along with centrifu- gal equipments. As it is obvious in Fig. 1, the crucible of furnace was in argon chamber with flow of 300 lit=h. Cylindrical samples with diameter and length of 10 and 45 mm were prepared in a zirconia mold. Finally, Received February 7, 2012; Accepted March 8, 2012 Address correspondence to Mansour Razavi, Materials and Energy Research Center (MERC), P.O. Box 14155-4777, Tehran, Iran; E-mail: m7816006@yahoo.com, m-razavi@merc.ac.ir Materials and Manufacturing Processes, 28: 31–35, 2013 Copyright # Taylor & Francis Group, LLC ISSN: 1042-6914 print=1532-2475 online DOI: 10.1080/10426914.2012.677916 31 Downloaded by [Mansour Razavi] at 22:35 12 January 2013