Radiotracer investigation of silver grain boundary diffusion and segregation in copper bicrystals at low temperatures: the direct determination of grain boundary diffusion coefficients

低温铜双晶中银晶界扩散和偏析的放射性示踪研究：晶界扩散系数的直接测定

• 批准号: 163598987
• 负责人: Professor Dr. Sergiy Divinski
• 金额: --
• 依托单位: Institut für Materialphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/163598987?language=en
• 关键词: Radiotracer; investigation; silver; grain; boundary

The project is focused on the experimental investigation of grain boundary diffusion of Ag in Cu bicrystals. Precisely characterized near Σ5 bicrystals will be investigated. We have recently improved the sensitivity and precision of the radiotracer measurements so that, for the first time, grain boundary diffusion in a bicrystal will be determined at such low temperatures that the so-called C-type kinetic conditions will be satisfied. These measurements will provide directly the values of the solute grain boundary diffusion coefficients, Dgb, which were never measured so far in bicrystals. At higher temperatures the measurements will be performed in the so-called B-type kinetics, which yield the triple product values, , P = s • δ • Dgb, where s is the segregation factor and ± the grain boundary width. The combination the low- and high-temperature measurements performed both along and perpendicular to the tilt axis of the oriented bicrystal is the key of the project and the product s • δ and its probable anisotropy will be determined for the first time. Considerable improvement of the current understanding of grain boundary diffusion and segregation phenomena is expected from this in its completeness so far unique investigation.

该项目的重点是铜双晶中银的晶界扩散的实验研究，我们将研究 Σ5 双晶附近的精确表征，我们最近提高了放射性示踪剂测量的灵敏度和精度，从而首次实现了晶界扩散。双晶中的扩散系数将在满足所谓的 C 型动力学条件的低温下确定，这些测量将直接提供溶质晶界扩散系数的值， Dgb，迄今为止从未在双晶中测量过。在较高温度下，测量将以所谓的 B 型动力学进行，产生三重乘积值， , P = s • δ • Dgb，其中 s 是偏析。沿和垂直于取向双晶倾斜轴进行的低温和高温测量的组合是该项目和产品的关键。 δ 及其可能的各向异性将首次被确定，在迄今为止的独特研究中，预计将大大改善目前对晶界扩散和偏析现象的理解。