Vacuum synthesis of composite powder of Al-Ni system for fabricating aluminum-matrix composite reinforced with Al3Ni particles

The composite powder containing Al3Ni and Al3Ni2 intermetallic compounds was obtained by vacuum synthesis to reinforce the aluminum matrix of the developed composite. For this purpose, nickel and aluminum powders were mixed in a ball mill, followed by heating the resulting mixture in vacuum to 650 degrees C to initiate an exothermic reaction between the powder components. To obtain an Al-Al3Ni composite, the synthesized composite powder and matrix aluminum powder were mixed in a mill, followed by compacting the resulting mixture and sintering the obtained samples in vacuum. It has been found that vacuum synthesis results in the formation of a composite powder with heterogeneous phase composition, including Al3Ni, Al3Ni2, Al4C3, and Al. Carbon formed as a result of thermal decomposition of stearin on the surface of aluminum particles reacts with aluminum to form aluminum carbide. After sintering the compacted mixture of aluminum and composite powders, a composite reinforced with Al3Ni and Al4C3 phases is formed. Tribological tests have shown that the obtained composite is a promising wear-resistant material with hybrid reinforcement by intermetallic and carbide phases.