How to compare superficial and intergranular segregation?: A new analysis within the mixed SMA-TBIM approach

被引：64

作者：

Berthier, F ^{[1
]}

Legrand, B

Tréglia, G

机构：

[1] Univ Paris Sud, LEMHE, F-91405 Orsay, France

[2] CEA Saclay, DECM, SRMP, F-91191 Gif Sur Yvette, France

[3] CNRS, CRMC2, F-13288 Marseille 9, France

来源：

ACTA MATERIALIA | 1999年 / 47卷 / 09期

关键词：

surface; segregation; grain boundaries; tight-binding calculation; computer simulation;

D O I：

10.1016/S1359-6454(99)00144-5

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The driving forces for intergranular segregation are much less known than the ones for super ficial segregation. In order to investigate the relation between grain-boundary and surface segregation, we have calculated the segregation energy for one impurity in both dilute limits for the Cu-Ag system. This is performed for the (001) surface on one hand and for the symmetrical tilt grain boundary Sigma = 5 (210) [001] on the other. These numerical results, obtained using N-body interatomic potentials derived from the second moment approximation (SMA) of the tight-binding scheme, are then discussed within an analytic model, the tight-binding Ising model (TBIM). This allows us to determine the relative role of the different driving forces in superficial and intergranular segregation. In particular competition or synergy between site and size effects strongly differ between surface and grain-boundary segregation. This study illustrates the efficiency of the mixed SMA-TBIM approach to predict and to analyse interfacial segregation. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. Ali rights reserved.

引用

页码：2705 / 2715

页数：11

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