IJE TRANSACTIONS C: Aspects Vol. 28, No. 9, (September2015) 1328-1335 Please cite this article as:A. Khajesarvi, G. Akbari,Effect of Mo Addition on Nanostructured Ni50Al50 Intermetallic Compound Synthesized by Mechanical Alloying, International Journal of Engineering (IJE), TRANSACTIONS C: Aspects Vol. 28, No. 9, (September 2015) 1328-1335 International Journal of Engineering Journal Homepage: www.ije.ir Effect of Mo Addition on Nanostructured Ni 50 Al 50 Intermetallic Compound Synthesized by Mechanical Alloying A. Khajesarvi*, G. Akbari Department of Materials Science and Engineering, Shahid Bahonar Institute of Technology, Kerman PAPER INFO Paper history: Received 26December 2014 Received in revised form 20June 2015 Accepted 03 September 2015 Keywords: Intermetallic Compounds Nanostructures X-Ray Diffraction Crystal Structure ABSTRACT The mechanical alloying process was used to synthesize the Ni50Al50−xMox nanocrystalline intermetallic compound using pure Ni and Al elemental powder. This process was carried out in the presence of various Mo contents as a micro-alloying element for various milling times. Structural changes of powder particles during mechanical alloying were studied by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Results showed that mechanical alloying in various combinations was completed after 48 h of milling time. Minimum crystallite size of the as-milled powders (∼10 nm) was achieved after introducing Mo and milling for 128 h. Also, lattice strain decreased with increasing milling time up to 48 h and again increased after 48 h of milling time. On the other hand, the presence of Mo significantly affected variation intensity of the lattice parameter and morphology of the powder particles. doi: 10.5829/idosi.ije.2015.28.09c.10 1. INTRODUCTION 1 The intermetallic compound NiAl which has drawn great attention owing to its physical properties can be exploited for high-temperature structural applications. The NiAl compound possesses high melting point (2184 °C), low density (5.86 g/cm 3 ), excellent thermal conduct, excellent oxidation, and corrosion resistance. However, lack of room temperature ductility and poor strength at high temperatures hinder its utilization as a candidate for replacing Ni-based superalloys. Therefore, many efforts have been made to reduce the brittleness of NiAl intermetallic compounds which can be classified as the modification of slip system by ternary or higher- order alloying [1], grain refinement [2, 3], and incorporation or precipitation of a ductile phase [4]. Also, improvement of the mechanical properties at high temperature has been reported through the second-phase incorporation [5]. Mechanical alloying (MA) can provide all the above-mentioned points simultaneously; therefore, this technique has been extensively applied to *Corresponding Author’s Email: alikhajesarvi@yahoo.com (A. Khajesarvi) synthesize nickel aluminide intermetallic. Although extensive studies have been carried out on these alloys, new investigations still continue to reveal attractive properties of the NiAl alloy system [2, 6-8]. NiAl intermetallic compound have some potential applications; therefore, it has been greatly considered by researchers and experts in many applications; such as hot sections of gas turbine engines for aircraft propulsion systems, electronic applications, coated superalloy, connecting semiconductors in the electronic and catalyst industry, electric heating elements, structural components of energy conversion systems, medical engineering, chemical industry, magnetic materials, hydrogen storage materials, and rolling rollers [9-12]. Mechanical alloying has been successfully applied for making nanocrystalline materials. Many researchers have reported making nanocrystalline NiAl intermetallic compound by MA [13, 14]. However, there are a few reports in the literature on the MA of ternary Ni–Al–Mo powders. Recently, great attention has been paid to the investigation of ternary systems by mechanical alloying. Zamora et al. [15] studied the Ni- Al-Mo system and reported that milling intensity had a major effect on the evolution of the microstructure and