Properties of highly controlled laser-melted aluminium–nickel eutectic alloys and fundamental insights on the dynamics of nonequilibrium thermal processing

The high strength of eutectic alloys holds utilitarian importance in the continuously advancing field of energy-efficient transportation. In this regard, aluminium eutectics show significant promise due to their superior mechanical properties without adding undesirable weight to the components. Here, we report the controlled fabrication of Al–Ni alloys with varying Ni concentration using the LPBF process under ambient conditions and microstructure evolution pathway via comprehensive process simulations. Our results establish a fundamentally premised structure–property mapping as a function of the processing parameters. The microstructural analysis reveals that the laser-melted materials exhibit a higher percentage of eutectic structures due to nonequilibrium cooling and enhanced mechanical properties (strength and wear resistance, hardness, etc.). Numerical simulations demonstrate that microstructural evolution is associated with a unique coupling of momentum, heat and mass transfer during the energy-directed thermal processing, following a different pathway at lower Ni concentrations. These findings not only exemplify a first-principle foundation for establishing the properties of additively manufactured speciality alloys but also pave the way for designing new materials for sophisticated target applications. These materials can achieve an optimal balance between the inception of intermetallic constituents and performance superiority for strength applications.