Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 150185

150185 - Atomistic and Multi-Scale Simulations of the Deformation Behaviors of Nano-Twinned Copper With Architected Texture 

Nano-twinned copper (nt-Cu) has gained considerable attention due to its exceptional mechanical properties, such as high strength and good ductility. The presence of twin boundaries within the copper matrix plays a crucial role in these properties, acting as barriers to dislocation motion and thereby enhancing strength without significantly compromising ductility. Understanding the deformation behaviors of nt-Cu, particularly with architected textures, is vital for the development of advanced materials with tailored properties. This study employs atomistic and multi-scale simulations to investigate the deformation mechanisms of nt-Cu, providing insights into its mechanical performance and potential applications.

This research utilizes a combination of atomistic simulations, specifically molecular dynamics (MD), and multi-scale modeling to explore the deformation behaviors of nt-Cu. The atomistic simulations are conducted using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) with embedded atom method (EAM) potentials to accurately describe the interatomic interactions in copper. Various nt-Cu samples with different twin boundary spacings and orientations are constructed to examine the influence of these parameters on the material's mechanical response.

In the multi-scale modeling approach, the results from the atomistic simulations serve as inputs for higher-scale continuum models. The continuum models employ Concurrent Atomistic Continuum (CAC) Method method to capture the microscale deformation behaviors while incorporating the nanoscale mechanisms observed in the MD simulations. This hierarchical modeling strategy allows for a comprehensive understanding of the deformation behaviors across different length scales.

The atomistic simulations reveal that the twin boundaries in nt-Cu significantly impede dislocation motion, leading to an increase in yield strength. The deformation mechanisms are found to be highly dependent on the twin boundary spacing and the loading orientation. For instance, samples with smaller twin boundary spacings exhibit higher strength due to the increased frequency of dislocation-twin boundary interactions. Additionally, the orientation of the twin boundaries relative to the loading direction affects the activation of different slip systems, influencing the overall mechanical response.

The multi-scale simulations further elucidate the role of twin boundaries in the macroscopic deformation behaviors. The CAC method, incorporating the atomistic findings, predict the stress-strain response of nt-Cu with varying textures. The results indicate that architected textures, designed to optimize twin boundary orientation and spacing, can enhance the mechanical performance of nt-Cu. The synergy between atomistic and continuum modeling provides a robust framework for predicting the material behavior under different loading conditions and designing nt-Cu with superior properties.

This research demonstrates the effectiveness of integrating atomistic and multi-scale simulations to investigate the deformation behaviors of nt-Cu with architected textures. The results provide valuable insights into the microscale mechanisms that drive the macroscopic mechanical performance of nt-Cu. By leveraging these insights, it is possible to design nt-Cu materials with tailored properties for specific applications, advancing the field of nanostructured materials and their engineering applications.

Presenting Author: Chang Yang North Carolina State University

Presenting Author Biography: He earned my BS and MS degrees in University of Washington and University of Pennsylvania, respectively. He is now a 2nd-year PhD student in Dr. Xiong’s group at NCSU. In the past years, He has taken all the core courses in finite element and solid mechanics. He delivered his first conference presentation at TMS 2024.

Authors:

Chang Yang North Carolina State University
Thanh Phan North Carolina State University
Liming Xiong North Carolina State University
Yipeng Peng University of Wyoming
Baozhi Cui Ames National Laboratory