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Dislocation nucleation from planar faults, such as grain boundaries and surfaces, is a fundamental plastic deformation event that influences the strength and fracture characteristics of polycrystalline metals and alloys. In this study, the free-end nudged elastic band method is used to determine the stress-dependent activation energy and dominant factors of dislocation nucleation, with edge and screw components, from surfaces (considered as planar faults) in body-centered cubic (BCC) metals. The energy barriers for dislocation nucleation in BCC metals mainly depend on Burgers vector and shear modulus, and they exceed those in FCC metals owing to the different nucleation morphology and affecting factors between BCC and FCC. For BCC Fe, an atomistically-informed model provides temperature and strain-rate-dependent stress for dislocation nucleation from a planar fault, enabling experimental comparison. The predictive model also shows the temperature- and shear stress-dependent frequency map of both dislocation nucleation from planar faults and kink-nucleation of pre-existing screw dislocations. The map indicates the necessity of a large shear stress for the dislocation nucleation and implies the dominant event depending on the dislocation density and applied shear stress. Free energy calculations also reveal temperature-dependent surface formation energy, which is a competitive event to dislocation nucleation at a crack tip under severe stress conditions, often discussed in ductile–brittle transition. The results provide the important fundamentals for dislocation-based modeling and design of BCC metals.

権利情報:

• Creative Commons BY Attribution 4.0 International
  

キーワード: BCC, Atomistic simulation, Surface, Dislocation, Activation energy, Free energy

刊行年月日: 2026-04-16

出版者: Elsevier BV

掲載誌:

• Journal of the Mechanics and Physics of Solids (ISSN: 00225096) vol. 213 106637

研究助成金:

• Precursory Research for Embryonic Science and Technology JPMJPR219A
• RIKEN hp230212
• National Institute for Materials Science
• RIKEN Center for Computational Science
• JST
• Japan Society for the Promotion of Science 24H00389
• Government of Japan Ministry of Education Culture Sports Science and Technology JPMXP1122684766
• Government of Japan Ministry of Education Culture Sports Science and Technology JPMXP1020230327

原稿種別: 出版者版 (Version of record)

MDR DOI:

公開URL: https://doi.org/10.1016/j.jmps.2026.106637

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更新時刻: 2026-10-28 13:16:54 +0900

MDRでの公開時刻: 2026-10-28 14:27:11 +0900