Microstructure evolution and mechanical properties of Cu-Ni functional gradient materials: Molecular dynamics simulation

QM Zhang and H Jin, MATERIALS TODAY COMMUNICATIONS, 47, 113132 (2025).

DOI: 10.1016/j.mtcomm.2025.113132

Functional gradient materials in the regulation of gradient distribution of components through mathematical functions is conducive to the achievement of performance-oriented design. This study adopted molecular dynamics simulation as the research method. The Cu-Ni alloy was selected as the object, and nine power-law function gradient models were constructed. Tensile and nanoindentation experiments were conducted at five characteristic temperatures: extremely low temperature (77 K), low temperature (220 K), normal temperature (300 K), high temperature (420 K), and extremely high temperature (600 K). The results of the study indicate that: The primary factors influencing the performance are the nickel content and the gradient distribution.An increase in the copper content will reduce the yield stress and hardness, but enhance plasticity. It is evident that the comprehensive mechanical properties attain an optimal level at a temperature of 77 K, accompanied by a severe dislocation accumulation phenomenon. An increase in temperature results in a decrease in Young's modulus, though this effect is relatively minor in terms of its influence on indentation behaviour. Dislocation evolution is jointly regulated by loading conditions and element gradients. The research advanced our understanding of the evolution of the microstructure of Cu-Ni alloys, providing a theoretical foundation for the design of FGM in extreme environments.

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