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1. Hydrogen-Induced Transformation of Dislocation Core in Fe and Its Effect on Dislocation Mobility

   Hasan, Md Shahrier; Bayat, Hadia; Delaney, Colin; Foronda, Christopher; Xu, Wenwu (February 2024, TMS 2024 153rd Annual Meeting & Exhibition Supplemental Proceedings (TMS 2024))

   In this research, we employ atomistic simulations to scrutinize the impact of hydrogen (H) on dislocation mobility in iron (Fe). Our study uncovers two critical aspects: Firstly, hydrogen atoms serve to stabilize the edge dislocation core, thereby elevating the shear stress threshold needed for dislocation mobilization. Secondly, hydrogen's influence on dislocation mobility is velocity-dependent; it enhances mobility at low velocities by diminishing lattice resistance but hampers it at high velocities due to increased viscous drag. These nuanced findings illuminate the multifaceted relationship between hydrogen atoms and dislocation mechanisms. They offer valuable insights for the development of materials with enhanced mechanical properties and contribute to strategies for mitigating hydrogen-induced material degradation. 

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2. One dislocation at a time

   https://doi.org/10.1038/s41563-023-01555-8  

   Bulatov, Vasily; Cai, Wei (June 2023, Nature Materials)

   The direct observation of enhanced dislocation mobility in iron by in situ electron microscopy offers key insights and adds to the ongoing debate on the mechanisms of hydrogen embrittlement. 

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3. Computational 3-dimensional dislocation elastodynamics

   https://doi.org/10.1016/j.jmps.2019.02.008  

   Cui, Yinan; Po, Giacomo; Pellegrini, Yves-Patrick; Lazar, Markus; Ghoniem, Nasr (May 2019, Journal of the Mechanics and Physics of Solids)
4. The three-dimensional elastodynamic solution for dislocation plasticity and its implementation in discrete dislocation dynamics simulations

   https://doi.org/10.1016/j.actamat.2023.118945  

   Yang, Junjie; Rida, Ali; Gu, Yejun; Magagnosc, Daniel; Zaki, Tamer A.; El-Awady, Jaafar A. (July 2023, Acta Materialia)
5. Dislocation avalanches in nanostructured molybdenum nanopillars

   https://doi.org/10.1116/6.0003254  

   Hsiao, Haw-Wen; Huang, Jia-Hong; Zuo, Jian-Min (March 2024, Journal of Vacuum Science & Technology A)

   We investigate intermittent plasticity in nanopillars of nanocrystalline molybdenum based on in situ transmission electron microscopy observations. By correlating electron imaging results with the measured nanopillar mechanical response, we demonstrate that the intermittent plasticity in nanocrystalline molybdenum is largely caused by dislocation avalanches. Electron imaging further reveals three types of dislocation avalanches, from intragranular to transgranular to cross-granular avalanches. The measured strain bursts resulted from avalanches have similar magnitudes to those reported for the molybdenum single-crystal pillars, while the corresponding flow stress in nanocrystalline molybdenum is greatly enhanced by the small grain size. Statistical analysis also shows that the avalanches behavior has similar characteristic as single crystals in the mean field theory model. Together, our findings here provide critical insights into the deformation mechanisms in a nanostructured body-centered-cubic metal. 

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