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 °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.