Lehtinen Arttu, Laurson Lasse, Granberg Fredric, Nordlund Kai, Alava Mikko J
Department of Applied Physics, COMP Centre of Excellence, Aalto University, Aalto, Espoo, P.O. Box 11100, FIN-00076, Finland.
Department of Physics, University of Helsinki, Helsinki, P.O. Box 43, FIN-00014, Finland.
Sci Rep. 2018 May 2;8(1):6914. doi: 10.1038/s41598-018-25285-z.
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 [Formula: see text] 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.
晶体材料的塑性变形由位错应力驱动运动的特征所支配。在承受外加应力的辐照钢的情况下，已知小位错环以及析出物会干扰位错运动，与纯晶体相比导致屈服应力增加。我们使用大规模三维离散位错动力学模拟研究析出物和间隙可滑移位错环对铁屈服应力的综合影响。使用我们最近的多尺度实现方法 [A. 莱蒂宁等人，《物理评论E》93 (2016) 013309] 将析出物纳入模拟，其中析出物的强度和钉扎机制由分子动力学模拟确定。在模拟中，我们观察到位错通过一种非典型的奥罗万机制克服析出物，这种机制是由铁中螺型位错段的铅笔滑移导致的。即使与位错的相互作用机制有很大不同，我们的结果表明，相对而言，在多滑移条件下，尺寸相似的析出物和位错环对屈服应力的贡献相同。
