Preparation of NiAl-Al2O3 intermetallic matrix nano composite powder by reactive milling

During the last decades significant research works have been devoted on development of structural intermetallics. Intermetallic compound NiAl possesses attractive high temperature properties which make the material a promising candidate for high temperature structural applications. However, it suffers from low ductility, brittle fracture and poor fabrication ability which are the major limitations for its usage [1-5]. Development of NiAl based nano composites by mechanochemical synthesis may help to overcome the shortages associated with the monolithic NiAl alloys. Alumina has been identified as suitable reinforcements for NiAl because it is thermodynamically compatible with NiAl [6,7]. Mechanochemistry is a term applied to process of reactive milling in which chemical reactions and phase transformation take place due to the application of mechanical energy [8]. A metal oxide may be reduced by a more reactive metal (reductant) to a metal or intermetallic compound.The mechanochemical process used in this study, includes an exchange reaction, where nickel oxide (NiO) is reduced by Al using high energy ball milling.