Mechanisms of self and impurity diffusion in Fe-Al intermetallic compounds

Fe-Al金属间化合物的自扩散和杂质扩散机制

• 批准号: 190209306
• 负责人: Dr. Tilmann Hickel
• 金额: --
• 依托单位: Department of Physics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/190209306?language=en
• 关键词: Mechanisms; self; impurity; diffusion; Fe

The diffusion data of alloys, such as vacancy formation energies, migration energies, diffusion activation energies and attempt frequencies, are basic information for materials design and materials processing. For several pure metals the involved mechanisms have already been studied using both experimental and theoretical methods. However, for intermetallic compounds the investigation of the mechanism of self- and impurity diffusion is challenging from experimental and theoretical point of view. Consequently, only limited knowledge exists in particular about atomic diffusion along grain boundaries in these materials. The proposed joint project is devoted to the investigation of self- and impurity diffusion mechanisms in Fe-Al alloys. On the one hand, the defect types and the defect micro-structures will be characterized by XRD, resistivity measurements and positron lifetime spectroscopy. On the other hand, the concentration and stable configurations of point defects in Fe-Al intermetallic compounds will be derived from first-principles calculations and will be used to optimize EAM interatomic potentials. Furthermore, first principles methods will also be used to determine self- and impurity diffusion activation energies/coefficients. The corresponding data will be compared with empirical results obtained from EAM based molecular dynamics calculations. Based on these extensive validity checks, the diffusion behavior of different atoms along typical grain boundaries within the investigated compounds will be simulated employing the empirical potentials. The resulting kinetic data for iron aluminides will be used to derive a diffusion model, which incorporates the effects of diffusion within a perfect lattice structure and along selected grain boundaries. In this way the project aims at understanding and quantifying the relevant diffusion mechanisms as a function of temperature and composition and at providing ideas to optimize atomic mobilities of various elements in iron aluminides.

合金的扩散数据，如空位形成能、迁移能、扩散激活能和尝试频率等，是材料设计和加工的基本信息。对于几种纯金属，所涉及的机制已经用实验和理论方法进行了研究。然而，对金属间化合物的自扩散和杂质扩散机制的研究从实验和理论的角度来看都是具有挑战性的。因此，只有有限的知识存在，特别是原子扩散沿晶界在这些材料。提出的联合项目致力于研究Fe-Al合金中的自扩散机制和杂质扩散机制。一方面，利用XRD、电阻率测量和正电子寿命谱对缺陷类型和微观结构进行表征；另一方面，Fe-Al金属间化合物中点缺陷的浓度和稳定构型将从第一性原理计算中得到，并将用于优化EAM原子间电位。此外，第一性原理方法也将用于确定自身和杂质扩散活化能/系数。相应的数据将与基于EAM的分子动力学计算得到的经验结果进行比较。基于这些广泛的有效性检查，不同原子沿典型晶界在所研究的化合物内的扩散行为将采用经验势模拟。所得到的铁铝化物动力学数据将用于推导扩散模型，该模型包含了在完美晶格结构内和沿选定晶界扩散的影响。通过这种方式，该项目旨在理解和量化作为温度和成分函数的相关扩散机制，并为优化铁铝化物中各种元素的原子迁移率提供思路。

项目成果

Thermodynamic and physical properties of FeAl and Fe3Al: an atomistic study by EAM simulation

FeAl 和 Fe3Al 的热力学和物理性质：通过 EAM 模拟进行原子研究

• DOI: 10.1016/j.physb.2012.08.025
• 发表时间: 2012-12
• 期刊: Physica B: Condensed Matter
• 作者: Ouyang, Yifang;Tong, Xiaofeng;Li, Chang;Chen, Hongmei;Tao, Xiaoma;Hickel, Tilmann;Du, Yong
• 通讯作者: Du, Yong