The occurrence of dislocation sites along grain boundaries is shown by transmission electron microscopy. Small thin sections of aluminum for these studies were obtained by electrolytic oxidation, with subsequent dissolution of the oxide. Dislocation sites along grain fragments in cold worked aluminum have been observed which, by Cottrell's formula, indicate grain orientation differences greater than 2° of arc. This method of examination makes possible the observation and analysis of dislocations in metals where boundaries are at other than extremely low angles of crystal misorientations. Also, it has been found useful for following the movement of dislocations within grains of the material and their migration to grain boundaries.

1.
W. L.
Bragg
,
Proc. Phys. Soc. (London)
52
,
54
(
1940
).
2.
J. M.
Burgers
,
Proc. Koninkl. Ned. Akad. Wetenschap.
42
,
293
(
1939
).
3.
P.
Lacombe
and
N.
Yannaquis
,
Métaux & Corrosion
22
,
35
(
1947
).
4.
A. H. Cottrell, Dislocations and Plastic Flow in Crystals (Oxford University Press, New York, 1953).
5.
Vogel
,
Pfann
,
Corey
, and
Thomas
,
Phys. Rev.
90
,
489
(
1953
).
6.
Hirsch, Horne, and Whelan, “Direct observations of the arrangement and motion of dislocations in aluminum,” Cavendish Laboratories, England (1956);
Phil. Mag.
,
1
,
677
(
1956
).
7.
Keller
,
Hunter
, and
Robinson
,
J. Electrochem. Soc.
100
,
411
(
1953
).
8.
D. E. Bradley and R. Phillips, “An explanation of an anomalous form of sub‐boundary in aluminum” (unpublished).
9.
R. D.
Heidenreich
,
J. Appl. Phys.
20
,
993
(
1947
).
This content is only available via PDF.
You do not currently have access to this content.