Characteristics of mechanical alloyed Ni-Al powder for sintering

Mechanical alloying was employed to obtain high-activity Ni-Al powder. The effects of mechanical alloying on the microstructure and characteristics of milled powder with a normal composition of Ni-22.89 at.% Al-0.5 at % B were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that a solution Ni (Al) was obtained after milling. During mechanical alloying, the milled powder obtains extra surface energy and crystalline energy because the crystallite size becomes fine and the lattice strain increases with the milling time prolonging. Furthermore, about 0.5 mol% oxide in the particles were formed after milling, and this kind of dispersed oxide is effective to improve the properties of the sintered alloy by dispersion strengthening. It is confirmed that Ni3Al alloy with outstanding properties has been prepared with mechanical alloyed powders.