Fabrication of Ni3Al by hot pressing from element powders

Ni3Al intermetallic was synthesized by hot pressing from element powders of nickel, aluminum, and boron. The influences of parameters on the properties of Ni3Al were investigated. The parameters include the particle size of nickel powder, adding or without boron powder, hot pressing temperature, etc. The properties include the density of hot-pressed samples, resultant ratio of Ni3Al phase, and bending strength. The microstructures of hot-pressed samples were investigated by X-ray diffraction and scan electronic microscopy, and the properties, such as density and bending strength, were also measured. The results show that a higher bending strength was obtained under the same hot pressing conditions by the fine nickel powder than the coarse one, and there is little difference about density. Boron powder added in this process accelerates the formation of Ni3Al and markedly increases the hot pressed density. In the temperature range of this study, the density increases along with the hot pressing temperature. Full dense Ni3Al samples were obtained under the condition of 860°C, 10 min, 45 MPa from Ni-22.89Al-0.5B powder.