Effects of alloying and Ni segregation at grain boundaries on the mechanical response of Cu-Ni alloys

YJ Chang and X Yang and X Guo and JQ Ren and HT Xue and JC Li and XF Lu, JOURNAL OF MATERIALS SCIENCE, 60, 11664-11678 (2025).

DOI: 10.1007/s10853-025-11104-0

Grain boundary segregation engineering is widely used as a means to control grain boundary stability and material strength. In this work, the effect of grain boundary segregation with different contents of Ni atoms on the mechanical properties of Cu-Ni alloy was studied by molecular dynamics (MD) method. It was found that the increase in material strength was mainly due to the alloying of the system and the fact that the segregation of Ni atoms at the grain boundaries could reduce the grain boundary energy and improve the stability of the grain boundaries. When the content of Ni atoms is 20%, the tensile strength and yield strength increase to 2.34 GPa and 2.31 GPa respectively. With the increase of Ni atom content, the grain boundary migration phenomenon is alleviated, and the grain boundary migration distance is shorter. Meanwhile, the dislocation density decreases with the increase of Ni atom content. As the barrier of grain boundaries to dislocations is strengthened, dislocations form obvious aggregation areas, and the intracrystalline deformation is mainly Shockley partial dislocation slip. The above results lay a foundation for the further application of Cu-Ni alloy.

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