Materials Transactions Online

Transactions of the Japan Institute of Metals, Vol. 14 No. 4 (1973) pp.256-260
© 1973 The Japan Institute of Metals

Dislocation Motion in Copper under Small Stresses*

Michio Ohta**, Yasuhiro Miura*** and Sadakichi Kitajima***

Dislocation motion in copper was studied by dislocation-etching before and under loading, and also after unloading.
Parallelepiped copper single crystals had a dislocation density of approximately 1×103/cm2 after thermal cyclic annealing. The dislocation etching under load was accomplished by hanging a small weight on the specimen in the etching solution.
Principal results are as follows:
(1) Dislocation locking stress due to impurity atoms was estimated to be less than 0.46 g/mm2, assuming that impurity atoms act only as pinning points.
(2) Lattice frictional stress for dislocation motion was evaluated to be, at most, 0.20 g/mm2, from the consideration of force balance on a bowed-out dislocation near the crystal surface.
(3) Both grown-in and multiplied dislocations were observed to move backward by unloading. Fresh dislocations made a back motion more easily.
(4) From an examination of the distance of dislocation motion and the average distance between grown-in forest dislocations, it is suggested that the main obstacle to moving dislocations is forest dislocations.

(Received August 14, 1972)

* This paper was originally published in the Journal of Japan Institute of Metals, 36 (1972), 908. (in Japanese)

** Faculty of Engineering, Kyushu University, Fukuoka. Present address: Faculty of Dentistry, Kyushu University, Fukuoka, Japan.

*** Faculty of Engineering, Kyushu University, Fukuoka, Japan.

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