High Angle Grain Boundary Structure in Widmanstätten Alpha Ti Microstructures

2022 ◽  
pp. 661-664
Author(s):  
S Wang ◽  
M Aindow
Keyword(s):  
Grain Boundary ◽  
Boundary Structure ◽  
High Angle ◽  
Grain Boundary Structure

Observations and implications of grain boundary dislocation networks in high-angle YBa2Cu3O7−δ grain boundaries

1990 ◽  
Vol 5 (5) ◽  
pp. 919-928 ◽  
Author(s):  
S. E. Babcock ◽  
D. C. Larbalestier
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Weak Link ◽  
Coincidence Site Lattice ◽  
Boundary Structure ◽  
High Angle ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Regular Networks

Regular networks of localized grain boundary dislocations (GBDs) have been imaged by means of transmission electron microscopy in three different types of high-angle grain boundaries in YBa2Cu3O7-δ, implying that these boundaries possess ordered structures upon which a significant periodic strain field is superimposed. The occurrence of these GBD networks is shown to be consistent with the GBD/Structural Unit and Coincidence Site Lattice (CSL)/Near CSL descriptions for grain boundary structure. Thus, these dislocations appear to be intrinsic features of the boundary structure. The spacing of the observed GBDs ranged from ∼10 nm to ∼100 nm. These GBDs make the grain boundaries heterogeneous on a scale that approaches the coherence length and may contribute to their weak-link character by producing the “superconducting micro-bridge” microstructure which has been suggested on the basis of detailed electromagnetic measurements on similar samples.

Texture and Grain Boundary Structure Dependence of Hillock Formation in Thin Metal Films

1998 ◽  
Vol 516 ◽  
Author(s):  
Matithew M. Nowell ◽  
David P. Field
Keyword(s):  
Grain Boundary ◽  
Integrated Circuit ◽  
Downstream Processing ◽  
Metal Films ◽  
Boundary Structure ◽  
High Angle ◽  
Structure Dependence ◽  
Local Character ◽  
Grain Boundary Structure ◽  
Hillock Formation

AbstractThe development of hillocks on metal films during annealing is detrimental to downstream processing of integrated circuit structures. This work focuses upon the local character of texture and grain boundary structure near hillocks in metal films. It is apparent from the results that local grain boundary structure and texture strength are important parameters in identifying locations in the films that are preferentially susceptible to failure under given conditions. Results in aluminum and platinum films indicate that non-(111) oriented grains preferentially contain hillocks. In addition, (111) oriented grains with boundaries characterized by high angle rotations about random axes are prone to hillock formation.

TEM Study of Secondary Grain Boundary Dislocations in Near-∑13, Near-∑17 and Near-∑29 [001] Twist Boundaries in Gold

1985 ◽  
Vol 43 ◽  
pp. 244-245
Author(s):  
S.E. Babcock
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Boundary Structure ◽  
Ordered Structure ◽  
Boundary Dislocation ◽  
High Angle ◽  
Extensive Search ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Twist Boundaries

In 1970, an extensive search by transmission electron microscopy (TEM) for evidence of ordered structure in high-angle [001] twist boundaries helped to establish the credibility of the DSC/CSL description of grain boundary structure. In this work, square grids of line contrast were found in boundaries for which the twist misorientation (Θ) was very near the special Σ5+ Σ13 and Σ17 Θ. The lines ran parallel to the primitive translation vectors (b(1) and b(2)) of the appropriate low-Σ DSC lattice, and their spacing correlated well with the spacing predicted by Frank's formula for dislocations with Burgers vectors b(1) and b(2). The images were interpreted as secondary grain boundary dislocation (SGBD) networks. Only for the near-Σ5 case was g•b analysis carried out to show that the line contrast was characteristic of b= 1/10 <310> type screw SGBD's.

Intrinsic Structure in Grain Boundaries and Boundary Mobility

1978 ◽  
Vol 36 (3) ◽  
pp. 380-391
Author(s):  
L.M. Clarebrough ◽  
C.T. Forwood
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Low Energy ◽  
Boundary Structure ◽  
Boundary Mobility ◽  
High Angle ◽  
Intrinsic Structure ◽  
Cornell University ◽  
Grain Boundary Structure ◽  
Energy Configurations

An outstanding experimental contribution to the knowledge of grain boundary structure in the 1970's is the work of Balluffi and his colleagues at Cornell University on artificially fabricated boundary interfaces in thin films of gold (e.g., Balluffi, Komem and Schober, 1972; Balluffi, Goodhew, Tan and Wagner, 1975). In particular, for high-angle boundaries they have shown that secondary grain boundary dislocations (g.b.d's.) do exist and accommodate a deviation from a low-energy misorientation corresponding to an exact C.S.L. relationship. Further, following the results of Spyridelis, Delavignette and Amelinckx (1967) they have shown that a network of g.b.d's. can act as a diffraction grating, causing extra reflections whose spacing is reciprocally related to the separation of the g.b.d's. (Balluffi, Sass and Schober, 1972). The description of high-angle grain boundaries in terms of secondary g.b.d's. accommodating a departure from an exact C.S.L. orientation is based solely on geometrical considerations, but it has been pointed out that other low-energy configurations may be preferred when account is taken of the nature of interatomic forces (Gleiter and Pumphrey, 1976; Hermann, Gleiter and Baro, 1976; Smith, Vitek and Pond, 1977).

Grain boundary structure observed by T.E.M

1978 ◽  
Vol 36 (1) ◽  
pp. 410-411
Author(s):  
P.J. Goodhew
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Lower Energy ◽  
Planar Defect ◽  
Boundary Structure ◽  
High Angle ◽  
Thin Specimen ◽  
Special Boundaries ◽  
Grain Boundary Structure

This paper reports some observations on gold by TEM which imply that the dissociation of a high angle grain boundary into two lower energy boundaries may occur extensively.It is well established that grain boundaries of any desired geometry can be created in gold by the welding together of thin single crystals. The resultant thin bicrystal specimens are ideally suited for immediate examination by TEM and many aspects of grain boundary structure and behaviour in such specimens have been studied or discussed. One particularly useful specimen configuration can be achieved if the bicrystal is annealed until its boundary migrates (lowering its total area) until it is perpendicular to the surface of the thin specimen. This specimen geometry has been used to study, inter alia, the faceting of grain boundaries.During a study of the behaviour of coincidence high angle boundaries (i.e. those special boundaries whose geometry is such that a fraction 1/Σ of the lattice sites in both crystals coincide) it was noticed that the boundary under observation was no longer a single planar defect.

Two Investigations into Grain Boundary Structure

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.

Relationships Between Grain Boundary Structure and Material Properties

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.

Sign in / Sign up

Export Citation Format

Share Document