金属中空位-氢团簇电荷转移应力失稳机制及相关现象研究

项目名称： 金属中空位-氢团簇电荷转移应力失稳机制及相关现象研究

项目编号： No.51474202

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 陈星秋

作者单位： 中国科学院金属研究所

项目金额： 85万元

中文摘要： 由于氢对金属合金性能和使役行为有重要影响，因此金属与氢的相互作用吸引着广泛的注意，特别是氢与金属空位、相界和位错等缺陷之间的相互作用已经成为相关问题的研究核心。在研究BCC类型金属空位-氢团簇生长的结构稳定性和电子结构时，我们发现空位-氢团簇的电荷转移应力失稳现象。这种现象和已经用来解释空位-氢团簇稳定方式不同，它表明氢在金属中的位置与金属中间隙电荷的分布密切相关，空位-氢团簇生长与其周围临近金属原子能供给的电荷密切相关；当最临近金属所供应给氢簇的电荷出现匮乏，导致氢团簇生长停止，此时伴随着应力能的急剧增加。本项目以深入研究电荷转移与应力失稳之间的关系为出发点，揭示金属缺陷与氢团簇生成、金属间隙电荷与氢原子占位、电荷转移与应力失稳之间的必然联系，探索该现象是否也在其它类型的合金甚至金属氢化物中普遍存在，从而为从原子层次理解相关的现象（比如氢脆和抗氢/储合金开发）提供机理上的启示。

中文关键词： 缺陷簇；计算模拟；电荷转移应力失稳；合金设计；金属-氢团簇

英文摘要： Interaction between hydrogen and metals has become an extensively discussed issue because it defines materials performance in hydrogen storage and hydrogen-resistant applications. Among them, the hydrogen cluster growth around various defects (vacancies, dislocations, grain boundaries, etc) becomes the center of many related investigations. According to our initial investigations we have discovered that a mechanism involving charge transfer induced strain destabilization to interpret the hydrogen cluster growth around vacancies in bcc-type metals. It has been found that the hydrogen trapping is strongly coupled with the interstitial charge distributions making the sites with the highest pre-existed accumulated charges. When the dominant charge transfer to hydrogen cluster is stemmed from further metal atoms beyond the nearest-neighboring shell surrounding the vacancy, a sharp increase of the strain energies universally occur. Here, we have proposed this project to investigate in details the interaction between the metallic defects and hydrogen cluster formation, between interstitial charges and hydrogen atomic preferences in the interstitial sites of the lattice space mainly through first-principles calculations and necessary experimental characterization. In particular, we will systematically focus on whether or not this proposed mechanism also matches other types of metals and metal hydrides with such the concerns of the universal relationship between charge transfer and strain destabilization. Our results are expected to have important insight for design of metal-based hydrogen storage materials and hydrogen-resistant structural materials as well as the related phenomenon of hydrogen embrittlement which quite often occurs in metals.

英文关键词： Defect cluster;Computational simulations;Charge transfer strain destabilization;Alloy design;Metal-Hydrogen interaction