Effect of milling parameters on the synthesis of Al-Ni intermetallic compound prepared by mechanical alloying

Nanocrystalline Al-Ni intermetallic compounds were synthesized with different percentages of nickel by mechanical alloying (MA) of elemental powders. In all MA runs, the ball-to-powder weight ratio was 10:1, the rotation speed was 350 rpm, and the milling time ranged from 4 to 12 h. The phase evolution and microstructural changes of the powders during MA were investigated by X-ray diffraction (XRD), scanning electron microscopy, and energy-dispersive X-ray spectroscopy analyses. The crystallite sizes of milled powders were estimated based on the broadening of XRD peaks using the Williamson-Hall formula. Results showed that an optimum MA time of 12 h led to the formation of solid solutions of Al-Zn-Mg and Ni, which can be added to many Al-Ni intermetallic compounds. Furthermore, an Al-Ni intermetallic phase with < 20 nm crystallite size was obtained.