Nanocrystalline Mg2Ni-based powders produced by high-energy ball milling and subsequent annealing

High-energy milling technique using a planetary ball mill and subsequent annealing have been employed for producing nanocrystalline powders based on Mg2Ni intermetallic compound. Characterization of the crystal structure of the milled product using X-ray diffractometry revealed that formation of Mg2Ni-based nanocrystallites occurred at ball to powder weight ratios of 10:1 and 20:1 after 30 and 12.5 milling hours, respectively. However, its kinetic and volume fraction were found to be greater at the higher ball to powder weight ratio. The calculated average Mg2Ni crystallite size was 10 nm at ball to powder weight ratio of 20:1 after 60 h of milling and showed decreasing with increasing ball to powder weight ratio. Subsequent annealing of the milled product at low milling time of 5 h resulted in the formation of the dominant Mg2Ni intermetallic compound with average crystallite size similar to the long period milled product.