当前位置: X-MOL 学术Nucl. Mater. Energy › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
The brittle-to-ductile transition in cold-rolled tungsten sheets: Contributions of grain and subgrain boundaries to the enhanced ductility after pre-deformation
Nuclear Materials and Energy ( IF 2.6 ) Pub Date : 2020-07-18 , DOI: 10.1016/j.nme.2020.100769
Carsten Bonnekoh , Philipp Lied , Stefan Zaefferer , Ute Jäntsch , Andreas Hoffmann , Jens Reiser , Michael Rieth

One of the key demands on tungsten (W) as designated plasma-facing material (PFM) is the capability to fulfill a structural function. Since W has refused ductilization strategies by alloying alone, the production of W materials with enhanced ductility has come into focus considering tailored microstructures. This work addresses the rolling-induced microstructural modifications of warm- and cold-deformed W sheets and is supplemented by a comprehensive fracture mechanical study as a fundament for correlations between the spatial distribution of boundaries and brittle-to-ductile transition (BDT) temperature. Here we show that an extended Hall–Petch-like relationship is well suited to describe the rolling-induced reduction in BDT temperature and moreover has the potential to reflect the anisotropic nature of the transition temperature in severely rolled W sheets. Using the data of warm- and cold-rolled W sheets and also of strongly recovered W, best description of the BDT temperature was achieved by using as microstructural variables (i) the mean spacing between boundaries which intersect with the crack front and (ii) the mean boundary spacing along the normal of the crack plane. Taking into account the similarity to recent simulative-derived relationships, our findings support the theory suggesting the stimulated dislocation nucleation at boundaries as the decisive factor for more effective shielding of the crack tip in UFG materials and, in consequence, significantly reduced BDT temperatures. Besides, this work gives strong indications that the reduction of the BDT temperature in UFG W is not related to coincidence site lattice (CSL) boundaries.



中文翻译:

冷轧钨薄板的脆性到延性转变:预变形后晶粒和亚晶界对延展性提高的贡献

作为指定的面向等离子体材料(PFM),对钨(W)的关键要求之一是具有完成结构功能的能力。由于W拒绝仅通过合金化来实现延展性策略,因此考虑到定制的微结构,具有增强延展性的W材料的生产已成为关注焦点。这项工作解决了轧制引起的热变形和冷变形W板的微观结构变化,并辅以全面的断裂力学研究作为边界空间分布与脆性至延性转变(BDT)温度之间相关性的基础。在这里,我们证明了扩展的霍尔-Petch-like关系非常适合描述轧制引起的BDT温度降低,而且有可能反映出在剧烈轧制的W薄板中转变温度的各向异性。使用热轧和冷轧W薄板的数据以及强烈回收的W的数据,通过使用(i)与裂纹前沿相交的边界之间的平均间距和(ii)作为微观结构变量,可以最好地描述BDT温度。沿裂纹平面法线的平均边界间距。考虑到与最近的模拟派生关系的相似性,我们的发现支持这一理论,表明边界处的受激位错形核是决定如何有效屏蔽UFG材料中裂纹尖端的决定性因素,并且 结果,大大降低了BDT温度。此外,这项工作有力地表明,UFG W中BDT温度的降低与符合位点晶格(CSL)边界无关。

更新日期:2020-07-18
down
wechat
bug