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Observation of the effect of solute segregation on grain boundary structure

Journal Article · · Scr. Metall.; (United States)

It is frequently observed that solute atoms segregate to grain boundaries in alloy systems where there is limited solubility in the solid solution. Auger spectroscopy has shown the presence of typically up to a monolayer of solute at internal interfaces in such systems. The practical consequence of such segregation is frequently the embrittlement of the grain boundary region, making it susceptible to fracture at relatively low stresses. It is of considerable interest to learn how the presence of the solute changes the mechanical properties of the boundary. Is the solute changing the chemical bonding across the interface as suggested by Messmer and Briant or is it changing the atomic structure, or perhaps both. In this paper an experiment is described which addresses the question of whether the presence of solute at the boundary influences the structure of the boundary. It is shown that in a small angle (001) twist boundary in the Fe-Au system, a small amount of Au causes a major change i the dislocation structure of the interface. These observations are evidence for the occurrence of a two dimensional phase transformation in the grain boundary.

Research Organization:
Department of Materials Science and Engineering, Cornell University, Ithaca, New York
OSTI ID:
6270897
Journal Information:
Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 18:2; ISSN SCRMB
Country of Publication:
United States
Language:
English