Effect of Electric Field on the Microstructure and Properties of NiAl Alloy Sheet Prepared by Foil Reaction Synthesis

NiAl alloy sheet was successfully prepared using current-assisted sintering, thus verifying the possibility of preparing a NiAl thin-wall component by current-assisted sintering and foil/foil reaction synthesis. Ni/Al laminated sheets were obtained by annealing at 550 °C at 5 MPa for 0.5 h; uniform NiAl alloy sheets were fabricated by annealing at 1150 °C at 15 MPa for 20 min. The experimental results showed that current-assisted sintering significantly reduced the reaction temperature and reaction time. Microstructural characterization revealed that the inter-diffusion ability of Al atoms is considerably weaker than that of Ni atoms. Molecular dynamics simulation confirmed these experimental results and showed that this difference becomes significant under the action of an electric field. The mechanism of synthesis of Ni/Al laminated sheets using current sintering is mainly determined by the diffusion behavior of Ni atoms.