Effects of precipitates and dislocation loops on the yield stress of irradiated iron

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • University of Helsinki

Abstract

Plastic deformation of crystalline materials is governed by the features of stress-driven motion of dislocations. In the case of irradiated steels subject to applied stresses, small dislocation loops as well as precipitates are known to interfere with the dislocation motion, leading to an increased yield stress as compared to pure crystals. We study the combined effect of precipitates and interstitial glissile 1/2(111)dislocation loops on the yield stress of iron, using large-scale three-dimensional discrete dislocation dynamics simulations. Precipitates are included in the simulations using our recent multi-scale implementation [A. Lehtinen et al., Phys. Rev. E 93 (2016) 013309], where the strengths and pinning mechanisms of the precipitates are determined from molecular dynamics simulations. In the simulations we observe dislocations overcoming precipitates with an atypical Orowan mechanism which results from pencil-glide of screw segments in iron. Even if the interaction mechanisms with dislocations are quite different, our results suggest that in relative terms, precipitates and loops of similar sizes contribute equally to the yield stress in multi-slip conditions.

Details

Original languageEnglish
Article number6914
Pages (from-to)1-12
JournalScientific Reports
Volume8
Issue number1
Publication statusPublished - 1 Dec 2018
MoE publication typeA1 Journal article-refereed

Download statistics

No data available

ID: 21094133