Investigation of shear responses and underlying deformation mechanisms of Cu/Ta nanolayered composite

KZ Xu and YQ Zhou and YX Chen and YH Gao and X Lei and ZN Yu and CJ Wang and JG Xie and FL Zhu, APPLIED SURFACE SCIENCE, 688, 162395 (2025).

DOI: 10.1016/j.apsusc.2025.162395

Nanoscale metallic multilayers (NMMs) are essential in micro/nanodevices because of their superior physical and mechanical properties. Differing from tension and compression, NMMs exhibit inhomogeneous localized plastic deformation during shear rather than a uniform overall strain response. The shear responses and deformation mechanisms of Cu/Ta NMMs at various temperatures are studied by molecular dynamics simulations. The results show the interfacial atomic structures get more disordered with increasing temperature. There are two yield points in shear stress- strain curves at lower temperatures, while only one yield point at higher temperatures. The shear strength and modulus decrease with temperatures. The specimen undergoes four deformation stages: the elastic stage, the yield stage of Cu, the yield stage of Ta, and the plastic flow stage. Its yield depends on dislocation nucleation and expansion of Ta, but the plastic deformation in the flow stage is jointly determined by the defect evolution of Cu and Ta. At high temperatures, defects are more prone to nucleation, while dislocation activities are suppressed. Compared to Ta, the suppression of high temperatures on dislocation activities of Cu is more pronounced. Cu is more susceptible to generating shear bands than Ta and high temperatures can promote the nucleation and growth of shear bands.

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