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W-foil: DuctilityIdentification of the mechanism of plastic deformation

W-箔：延展性塑性变形机制的识别

基本信息

批准号：
250335026
负责人：
Dr.-Ing. Jens Reiser
金额：
--
依托单位：
Institut für Angewandte Materialien - Angewandte Werkstoffphysik (IAM-AWP)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/250335026?language=en
关键词：
foil DuctilityIdentification mechanism plastic deformation

项目摘要

Tungsten (W) is he metal with the highest melting point of all metals ((TS = 3422°C) and is therefore often considered as primary candidate for high temperature applications in energy conversion systems. However W has two major drawbacks: (i) a catastrophic oxidation behavior beyond 600°C as well as (ii) a low fracture toughness, KIC, or a high brittle-to-ductile transition temperature (BDTT) measured by Charpy. Especially for the last problem an interesting solution was found. This solution consists of the ductilisation of W through the synthesis of a W laminate (W multilayer) made of W foils. W foils have a high fracture toughness and are even ductile at room temperature. By assembling and joining we succeeded in expanding the toughness of the foil to the bulk.Many publications point out that W can be ductilised by cold working. However this is only described by a phenomenological approach and there is no understanding of the underlining mechanism. Especially the mechanism of the plastic deformation of W foil or in general of bcc UFG materials is not understood in its whole.Within the framework of this proposal the influence of (i) the high amount of mobile edge dislocations, (ii) the grain refinement, as well as (iii) the dislocation annihilation on the free surface on the extraordinary ductility of W foil, thickness 0.1 mm, will be assessed. Doing this the mechanism of the plastic deformation will be determined in a direct (tensile tests, TEM) as well as in an indirect manner (SRS, activation volume) and the results obtained will be correlated.

钨（W）是所有金属中熔点最高的金属（TS = 3422°C），因此通常被认为是能量转换系统中高温应用的主要候选材料。然而，W具有两个主要缺点：（i）超过600°C的灾难性氧化行为以及（ii）低断裂韧性KIC或通过夏比测量的高脆韧转变温度（BDTT）。特别是对于最后一个问题，我们找到了一个有趣的解决方案。该解决方案包括通过合成由W箔制成的W层压体（W多层）来使W延展。W箔具有高的断裂韧性，并且在室温下甚至是可延展的。通过组装和连接，我们成功地将箔的韧性扩展到了本体。许多出版物指出，W可以通过冷加工而延展。然而，这只是描述了一个现象学的方法，并没有理解的基础机制。特别是W箔或一般bcc UFG材料的塑性变形机制尚未完全理解。在本建议的框架内，将评估（i）大量移动的刃位错，（ii）晶粒细化，以及（iii）自由表面上的位错湮灭对厚度为0.1 mm的W箔的非凡延展性的影响。这样做的塑性变形的机制将被确定在一个直接的（拉伸试验，TEM）以及在一个间接的方式（SRS，激活体积）和获得的结果将是相关的。