Reaction synthesis of nickel/aluminide multilayer composites using Ni and Al foils: Microstructures, tensile properties, and deformation behavior

Full-density nickel/aluminide multilayer composites were successfully fabricated by reaction synthesis using Ni and Al foils. The Al is the dominant diffusing species, and Ni₂Al₃ is the first phase formed during reaction between the Ni and Al foils at 620 °C. The reaction mechanism is such that only Al atoms can diffuse through the Al₂O₃ films formed on the Al foils, and the Al atoms then transform into Ni₂Al₃ by reaction with Ni. The Ni and Ni₃Al layers in the composites can therefore cooperatively deform through slipping of dislocations in the Ni and Ni₃Al layers through the Ni₃Al/Ni interfaces. Thus, Ni/Ni₃Al multilayer composites exhibit high ultimate tensile strengths and large elongations (1050 MPa and 18.2 pct).