Inverse Grain-Size Effect on Twinning in Nanocrystalline Ni

作者：Xiaolei Wu, Yuntian T. Zhu · 发表于：Physical Review Letters · 年份：2008 · DOI：10.1103/physrevlett.101.025503 · 被引用次数：222 · 研究领域：Microstructure and mechanical properties、nanoparticles nucleation surface interactions、Aluminum Alloys Composites Properties

A long-standing controversy exists between molecular dynamics simulations and experiments on the twinning propensity of nanocrystalline (NC) face-centered-cubic metals. For example, three-dimensional molecular dynamics simulations rarely observed twins in NC Ni, whereas experiments readily observed them. Here this discrepancy is resolved by experimental observation of an inverse grain-size effect on twinning. Specifically, decreasing the grain size first promotes twinning in NC Ni and then hinders twinning due to the inverse grain-size effect. Interestingly, no inverse grain-size effect exists on stacking fault formation. These observations are explained by generalized planar fault energies and grain-size effect on partial emissions.