Experimental measurements of the correlation factor for solute diffusion

溶质扩散相关因子的实验测量

• 批准号: 281815943
• 负责人: Professor Dr. Sergiy Divinski
• 金额: --
• 依托单位: Department of Physics and Astronomy
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/281815943?language=en
• 关键词: Experimental; measurements; correlation; factor; solute

Substitutional atoms diffuse by jumping into neighboring, vacant lattice sites. But an atom that has just jumped may jump backwards into the vacancy so that, compared with a hypothetical random walk process, the net 'forward movement' of the atom is decreased by a so-called correlation factor. For host atoms, the correlation factor is simply a numerical constant reflecting the diffusion mechanism and geometry of the diffusion sublattice. Solute atoms, on the other hand, interact with vacancies and modify the local concentration of vacancies and microscopic jump rates. Such solute-vacancy interactions make the correlation factor for solute diffusion highly sensitive to details of the atomic interactions and temperature. Its measurement should help identify diffusion mechanisms, interpret the interactions, and facilitate reliable predictions of diffusion rates via atomistic simulations. As yet there has been no direct determination of a correlation factor for solute diffusion. The present proposal aims to do that for the first time by combining results of complementary measurements of the diffusion coefficient and jump-rate of a solute in the same matrix. These will be measured using the radiotracer technique and perturbed angular correlation spectroscopy, respectively. To within a constant, the correlation factor is simply the ratio of the diffusion coefficient and the jump-rate. A3B phases having the common L12 structure have been chosen for study as a benchmark system. Diffusion in these ordered phases has attracted enormous interest because there exists a number of possible diffusion mechanisms and likely occurrence of inter- and intra-sublattice jumps for solutes with different activation energies. The influence of composition and temperature on the correlation factor will be determined. Specifically, correlation factors for diffusion of cadmium solutes will be measured for In-rich and In-poor compositions of the In3Gd phase at a variety of temperatures. Different diffusion mechanisms may operate at the two compositions, which will be obtained using samples having the opposing phase boundary compositions. State-of-the-art facilities at Münster University (radiotracer laboratory) and at Washington State University, USA (perturbed angular correlation laboratory) will enable measurements to be made having the required accuracy. In the absence of any previous measurements, results are likely to surprise.

替代原子通过跳入附近的空晶格位点扩散。但是，刚刚跳跃的原子可能会向后跳入空缺，因此，与假设的随机行走过程相比，原子的净“向前运动”通过所谓的相关因子降低。对于宿主原子，相关因子只是一个数值常数，它反映了扩散sublattice的扩散机理和几何形状。另一方面，溶质原子与空位相互作用，并修改空缺的局部浓度和微观跳跃速率。这种可溶性胶合相互作用使固体扩散的相关因子对原子相互作用和温度的细节高度敏感。它的测量应有助于确定扩散机制，解释相互作用以及通过原子模拟对扩散率的友好预测。到目前为止，还没有直接确定固体扩散因子的相关因子。本提案的目的是首次结合相同基质中固体扩散系数和跳跃率的互补测量结果。这些将分别使用放射性示意剂技术和扰动的角相关光谱进行测量。在常数之内，相关因子仅仅是扩散系数和跳跃速率的比率。具有共同L12结构的A3b阶段已被选择作为基准系统。这些有序阶段的扩散引起了巨大的关注，因为存在许多可能的差异机制，并且可能发生不同激活能量的太阳能中的众议院间和公共性跳跃。组成和温度对相关因子的影响将得到确定。具体而言，将在多种温度下，将测量IN3GD阶段的富裕和人体内组成的镉溶液差异的相关因子。不同的差异机制可以在两个组合物处运行，这将使用具有相对相边界组成的样品获得。穆斯特大学（Radiotracer Laboratory）和美国华盛顿州立大学的最先进的设施（受扰动的角相关实验室）将使能够具有必要的准确性进行测量。在没有任何以前的测量值的情况下，结果可能会令人惊讶。

项目成果

Composition dependence of tracer diffusion coefficients in Fe–Ga alloys: A case study by a tracer-diffusion couple method

• DOI: 10.1016/j.actamat.2020.10.065
• 发表时间: 2020-08
• 期刊: arXiv: Materials Science
• 作者: G. Muralikrishna;B. Tas;N. Esakkiraja;V. Esin;K. C. Kumar;I. Golovin;I. Belova;G. Murch;A. Paul;S. Divinski

Atomic transport in B2-ordered Al(Fe,Ni) alloys: Tracer-interdiffusion couple approach

• DOI: 10.1016/j.intermet.2020.106920
• 发表时间: 2020-11
• 期刊: Intermetallics
• 影响因子: 4.4
• 作者: G. Muralikrishna;V. Esin;K. Kulkarni;B. S. Murty;G. Wilde;S. Divinski

Novel Multicomponent B2-Ordered Aluminides: Compositional Design, Synthesis, Characterization, and Thermal Stability

• DOI: 10.3390/met10111411
• 发表时间: 2020-10
• 期刊: Metals
• 影响因子: 2.9
• 作者: G. Muralikrishna;A. Esther;K. Guruvidyathri;P. Watermeyer;C. Liebscher;K. Kulkarni;G. Wilde;S. Divinski;B. S. Murty

Diffusion, defects and understanding the growth of a multicomponent interdiffusion zone between Pt-modified B2 NiAl bond coat and single crystal superalloy

• DOI: 10.1016/j.actamat.2020.04.016
• 发表时间: 2020-08-15
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Esakkiraja, Neelamegan;Gupta, Ankit;Paul, Aloke
• 通讯作者: Paul, Aloke

Tracer diffusion in ordered pseudo-binary multicomponent aluminides

• DOI: 10.1016/j.scriptamat.2019.11.044
• 发表时间: 2020-03
• 期刊: Scripta Materialia
• 影响因子: 6
• 作者: M. G.;M. Vaidya;B. S. Murty;S. Divinski;G. Wilde