Compensation Effect for Grain Boundary Diffusion in a Bicrystalline Experiment
Compensation Effect for Grain Boundary Diffusion in a Bicrystalline Experiment
复制标题
双晶实验中晶界扩散的补偿效应
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
L. Shvindlerman
中科院分区：
文献类型：
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作者：
A. Aleshin;R. Faulkner;D. Molodov;L. Shvindlerman
本文致力于研究晶界扩散的补偿效应问题，即晶界扩散系数的指前因子与激活能的线性关系。讨论了晶界扩散作为热激活过程的特点，即偏析因子K和晶界宽度δ的变化对扩散速率的影响。设计了一个特殊的扩散实验来估计三元产物KδDGB（DGB是GB扩散系数）的各个组成部分的贡献。实验是用Al双晶进行的。估算了GB结构变化引起的GB宽度δ和偏析因子K值的变化。结果表明，DGB是三重积中主要的GB结构敏感参数。这种情况使我们能够考虑GB在铝双晶作为一系列均匀的对象，并描述GB扩散的补偿温度Tc和“障碍”相的动力学。Zn和Ge在Al双晶中的GB扩散的Tc值实际上是相同的，分别等于709和706 K。讨论了“势垒”相的性质。
The paper is devoted to the problem of the compensation effect for grain boundary (GB) diffusion, i.e. the linear dependence of the pre-exponential factor of the GB diffusion coefficient on the activation energy. Specific features of GB diffusion as a thermally activated process namely, the influence of segregation factor, K, and variation of the GB width, δ, on the diffusion rate are discussed. A special diffusion experiment was designed to estimate the contribution of the separate component parts of the triple product, KδDGB (DGB is the GB diffusion coefficient). The experiment was performed with Al bicrystals. The variation of the GB width δ, and a value of the segregation factor K, due to GB structure change are estimated. It is concluded that DGB is the main GB structure-sensitive parameter in the triple product. This circumstance allows us to consider the GBs in Al bicrystals as a series of uniform objects and to describe the kinetics of GB diffusion in terms of the compensation temperature Tc and a “barrier” phase. The value of Tc for GB diffusion of Zn and Ge in Al bicrystals is practically the same and equals 709 and 706 K, respectively. The character of the “barrier” phase is discussed.