Atomic scale investigation of grain boundary structure role on intergranular deformation in aluminium

ABSTRACTWe calculated the atomic structure of the (310)[001] symmetric tilt grain boundary (GB) in B2 ordered Fe-Al, using empirical and ab initio potentials. Including a proper treatment of the influence of small departures from bulk B2 stoichiometry on chemical potentials through a thermodynamic point-defect model, we obtain low energy GB variants geometrically close to the usual ones deduced from the coincidence site lattice (CSL) theory. In Al-rich alloys, both methods predict GB Al segregation whereas in Fe-rich alloys, the empirical (resp. ab initio) approach leads to Fe (resp. Fe or no) segregation. With both methods, strong GB chemical effects triggered by the bulk composition appear, showing that in B2 Fe-Al, GB properties may be strongly influenced by small bulk composition changes.

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Direct Determination of Grain Boundary Atomic Structure in SrTiO3

MRS Proceedings ◽

10.1557/proc-357-115 ◽

1994 ◽

Vol 357 ◽

Cited By ~ 2

Author(s):

M.M. McGibbon ◽

N.D. Browning ◽

A.J. McGibbon ◽

M.F. Chisholm ◽

S.J. Pennycook

Keyword(s):

Grain Boundary ◽

Atomic Structure ◽

Light Element ◽

Direct Determination ◽

Atomic Scale ◽

Boundary Structure ◽

Structure Property ◽

Contrast Imaging ◽

Grain Boundary Structure ◽

Tilt Boundaries

AbstractIn the electroceramic SrTiO3 the grain boundary atomic structure governs a variety of electrical properties such as non-linear I-V characteristics. An understanding of this atomic structure-property relationship for individual grain boundaries requires a technique which probes both composition and chemical bonding on an atomic scale. Atomic structure models for [001] tilt boundaries in SrTiO3 bicrystals have been determined directly from experimental data, by combining high-resolution Z-contrast imaging to locate the cation columns at the boundary, with simultaneous electron energy loss spectroscopy to examine light element coordination at atomic resolution. In this paper we compare and contrast the grain boundary structure models of symmetric and asymmetric boundaries in SrTiO3.

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Two Investigations into Grain Boundary Structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080833 ◽

1977 ◽

Vol 35 ◽

pp. 688-691

Author(s):

P. Humble

Keyword(s):

Grain Boundary ◽

Dark Field ◽

Boundary Structure ◽

Boundary Dislocation ◽

Bright Field ◽

Intrinsic Structure ◽

Weak Beam ◽

Grain Boundary Structure ◽

Independent Information ◽

Diffraction Patterns

There has been sustained interest over the last few years into both the intrinsic (primary and secondary) structure of grain boundaries and the extrinsic structure e.g. the interaction of matrix dislocations with the boundary. Most of the investigations carried out by electron microscopy have involved only the use of information contained in the transmitted image (bright field, dark field, weak beam etc.). Whilst these imaging modes are appropriate to the cases of relatively coarse intrinsic or extrinsic grain boundary dislocation structures, it is apparent that in principle (and indeed in practice, e.g. (1)-(3)) the diffraction patterns from the boundary can give extra independent information about the fine scale periodic intrinsic structure of the boundary.In this paper I shall describe one investigation into each type of structure using the appropriate method of obtaining the necessary information which has been carried out recently at Tribophysics.

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Relationships Between Grain Boundary Structure and Material Properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001550 ◽

1980 ◽

Vol 38 ◽

pp. 366-369

Author(s):

Brian Ralph ◽

Barlow Claire ◽

Nicola Ecob

Keyword(s):

Grain Boundary ◽

Material Properties ◽

Main Property ◽

Grain Structure ◽

Boundary Structure ◽

Grain Boundary Structure ◽

Property Changes

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.

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