Controlled Development and Prediction of Zero-flux Planes, Diffusion Paths and Diffusion Structures in Multicomponent and Multiphase Systems

本研究旨在探索Cu-Ni-Zn系统中α（a，fcc）和β（B，bcc）单相和多相合金在775 ℃下的等温扩散现象。一个主要目的是通过在扩散区内相邻间隔开的一系列零通量平面（ZFP）的发展来减少组分的相互扩散。该研究还调查了内在和相互扩散，以及零通量平面，扩散路径和扩散结构的发展，在扩散耦合的特点是控制热力学力的两个组件。本研究的另一个目标是开发一个用户友好的多组分扩散程序，该程序具有多组分扩散数据库，能够分析和预测多组分组件中的扩散路径和扩散结构。实验部分涉及用a和B Cu-Ni-Zn合金组装无限和有限扩散偶，所述合金具有Ni等活度线上的成分。这些电偶对被组装成使得末端合金之间的Zn和Ni的活性差异大小相同但符号不同。所有的电偶都用电子显微镜技术进行了分析。用扫描电子显微镜和透射电子显微镜研究了多相偶中扩散结构的发展。这些受控实验有助于更好地理解和洞察的内在和相互扩散现象，以及ZFP在多组分系统的发展。预计计划中的扩散代码的开发将作为多组分、多相系统中扩散路径分析和预测的教学、研究和设计工具，并可在教育和工业领域中接触到大量受众。

This grant explores the phenomenon of isothermal diffusion at 775oC in alpha (a, fcc) and beta (b, bcc) single phase and multiphase alloys in the Cu-Ni-Zn system. A major objective is to reduce interdiffusion of a component through development of a series of zero-flux planes (ZFP) adjacently spaced within the diffusion zone. The study also investigates intrinsic and interdiffusion, as well as development of zero-flux planes, diffusion paths and diffusion structures, in diffusion couples characterized by controlled thermodynamic forces for two of the components. Other goal of the proposed investigations is to develop a user-friendly, multicomponent diffusion code equipped with a library of diffusion data for several multicomponent systems, and capable of analysis and prediction of diffusion paths and diffusion structures in multicomponent assemblies.%%%The experimental portions involve assembling infinite and finite diffusion couples with a and b Cu-Ni-Zn alloys having compositions on an isoactivity line for Ni. These couple pairs are so assembled that the activity differences for Zn and Ni between the terminal alloys are identical in magnitude but different in sign. All couples are analyzed by electron microbrobe techniques. Diffusion structure development in multiphase couples is examined by scanning electron microscopy and transmission electron microscopy. These controlled experiments contribute to better understanding and insights into the intrinsic and interdiffusion phenomena as well as ZFP development in multicomponent systems. The development of the planned diffusion code is expected to serve as a teaching, research and design tool for the analysis and prediction of diffusion paths in multicomponent, multiphase systems and can reach a large audience in the fields of education and industry.***