Liu Yuan, Duan Yanfeng, Zhang Junjie
School of Astronautics, Harbin Institute of Technology, Harbin 150001, China.
Research Department of Structure Design and Simulation, Graduate School of Hubei Aerospace Technology Academe, Wuhan 430040, China.
Nanomaterials (Basel). 2018 Sep 6;8(9):695. doi: 10.3390/nano8090695.
Nanotwinned metals exhibit superior mechanical properties due to unique dislocation⁻twin boundary interactions. In the present work, we elucidate the microscopic deformation mechanisms and their correlations with the macroscopic mechanical response of nanotwinned Al containing inclined twin boundaries under nanoindentation by means of molecular dynamics simulations. The effect of twin boundary orientation with respect to the indented surface on the nanoindentation is evaluated. Simulation results reveal that dislocation slip, dislocation⁻twin boundary interaction, and twin boundary migration operate in parallel in the plastic deformation of nanotwinned Al. The inclination angle of twin boundaries with respect to indented surface has a strong influence on the interaction between individual deformation modes, which in turn leads to the anisotropic indentation behavior of nanotwinned Al.
由于独特的位错-孪晶界相互作用，纳米孪晶金属表现出优异的力学性能。在本工作中，我们通过分子动力学模拟阐明了纳米孪晶铝中含倾斜孪晶界在纳米压痕下的微观变形机制及其与宏观力学响应的相关性。评估了孪晶界相对于压痕表面的取向对纳米压痕的影响。模拟结果表明，在纳米孪晶铝的塑性变形中，位错滑移、位错-孪晶界相互作用和孪晶界迁移同时起作用。孪晶界相对于压痕表面的倾斜角度对各变形模式之间的相互作用有很大影响，进而导致纳米孪晶铝的各向异性压痕行为。
