Insight of Ni Content and Gradient Structure on Tensile Properties and Deformation Mechanism of CuNi Alloy

ABSTRACT In the present contribution, molecular dynamics (MD) simulations are employed to investigate the tensile deformation of CuNi alloys. It focuses on the effects of Ni content, gradient structural sequence, and temperature on the mechanical response and deformation mechanisms of the alloy. The results indicate that the tensile strength and yield strength of CuNi alloys increase with higher Ni content, attributed to the enhancement of short‐range ordering and grain boundary stabilization. Conversely, with increasing temperature, the intensified atomic thermal vibrations reduce the extent of short‐range ordering and destabilize grain boundaries, consequently degrading the mechanical properties of the alloy. CuNi alloys with a straight gradient structure exhibit the highest tensile strength and yield strength. In the initial deformation stage, the straight gradient structure primarily bears stress through the fine grains. As strain increases, the stress is transferred to the larger grains. However, the coordinated deformation capability of the straight gradient structure is stronger than that of the core fine‐grained structure, while in the core coarse‐grained structure, stress is transmitted from the larger grains to the smaller grains. This work provides a theoretical basis and technical support for the strengthening strategies of CuNi alloys via microstructural design.