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固溶体中的化学结构单元与合金成分设计 被引量:1

Chemical Units in Solid Solutions and Alloy Composition Design
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摘要 工业合金具有特定的牌号成分,理解这些特殊成分背后的结构根源可以从原子结构层面上指导新合金的研发,有效缩短工业合金的制备流程。工业合金多以固溶体结构为基础,而固溶体以化学近程有序为结构特征,长期以来,人们只能以统计方式获得溶质元素偏离平均结构的程度,由于缺失描述近程序的精确结构分析方法,导致无法构建能够指导合金成分设计的有效结构模型。既然优质合金均具有特殊成分,这些成分背后一定对应于类似于分子的特定结构单元。本课题组提出了一种全新的近程有序描述方式——团簇加连接原子。该模型认为,对于固溶体合金,存在理想满足原子间相互作用的化学结构单元,仅涵盖第一近邻团簇以及若干次近邻的连接原子,可表示为团簇成分式的形式:[团簇](连接原子)。这种团簇式类似于化学物质的分子式,是代表合金平均结构的最小结构单元。通过将Friedel振荡机制引入到团簇加连接原子模型中,建立了固溶体的团簇共振模型,给出了团簇的球周期近邻堆垛方式,从而解决了原子密度的关键问题。结果表明,团簇成分式中所包含的原子个数正比于体系的平均原子密度和团簇半径的立方,由此可以定量地计算出理想化学结构单元的具体形式。本文列举了根据公式计算得到的典型铜基二元合金最佳化学结构单元,计算所得成分与最常用工业合金高度吻合。本工作为成分设计提供了一种新的实用方法。 Industrial alloys all have specific chemical compositions as standardized in specifications.Understanding the structural origin of special compositions for these solid-solution alloys is significant to shortening the development of new industrial alloys. It is well accepted that all alloys are based on solid solutions characterized by chemical short-range ordering. Previously it was only possible to describe the deviation of solute distribution from average mode in a statistical manner. The lack of an accurate structural tool to address the characteristic short-range-order structures constitutes the major obstacle in establishing an effective structural model that allows precise composition design for alloys. Since alloys with good comprehensive performance do have specific chemical compositions, their compositions should correspond to molecule-like specific structural units. After a long effort of more than a decade, we have de-veloped a new structural tool, so-called the cluster-plus-glue-atom model, to address any short-range-ordered structures. In particular, solid solutions can be understood as being constructed from the packing of special chemical units covering only the nearest-neighbor cluster and a few glue atoms located at the next outer shell, expressed in molecule-like cluster formula [cluster](glue atoms). Such units represent the smallest particles that are representative of the whole structures, just like molecules do for chemical substances. After introducing Friedel oscillation, the cluster-plus-glue-atom model is turned into the cluster-resonance model that provides also the inter-cluster packing modes. Ideal atomic density is hence obtained which is only proportional to the number of atoms in the unit and the cube of the cluster radius.The calculation of chemical unit is then possible and is conducted in typical binary Cu-based industrial alloys. The calculated formulas give chemical composition that highly agree with the most popular alloy specifications. The work demonstrates its high pot
作者 董闯 董丹丹 王清 DONG Chuang 1, DONG Dandan 2, WANG Qing 1 (1 Key Laboratory for Materials Modification by Laser, Ion and Electron Beam, Ministry of Education Dalian University of Technology, Dalian 116024, China 2 College of Physical Science and Technology, Dalian University, Dalian 116622, China)
出处 《金属学报》 CSCD 北大核心 2018年第2期293-300,共8页 Acta Metallurgica Sinica
基金 国家自然科学基金项目No.11674045
关键词 化学结构单元 团簇加连接原子模型 固溶体 近程有序 铜基二元工业合金 chemical unit cluster-plus-glue-atom model solid solution short-range order Cu-based industrial alloy
作者简介 董闯,男,1963年生,教授,博士 通讯作者 董闯,dong@dlut.edu.cn,主要从事材料的原子结构模型及成分设计研究
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参考文献2

  • 1董丹丹..金属玻璃和固溶体合金的成分根源:近程序结构单元[D].大连理工大学,2017:
  • 2李正中著..固体理论[M].北京:高等教育出版社,1985:577.

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