抄録
Plastic deformation of aluminium single crystals was studied through Kikuchi lines of electron diffraction by the introduction of a new technique: large angle convergent beam method. By this method the irradiated area on the specimen surface can be reduced to 5×20 sq. microns and therefore laminar regions and deformation bands can be studied seperately. For 99.99% aluminium it was found that in laminar regions the distortion is so small that Kikuchi lines are produced even at 10% elongation and that in deformation bands it is large enough to extinguish Kikuchi lines. For 99.55% aluminium, at any place in the crystal the distortion is so large that Kikuchi lines become diffuse at about 3% elongation and are extinguished at about 7% elongation. It was confirmed in all cases that no rotation occurs in the slip plane. The interior of elongated crystals was studied after removal of the surface layer by electro-polishing. Irrespective of the purity of crystals, no recognizable difference was found in the surface layer and in the interior. The order of dislocation density was estimated through Kikuchi line experiment. The results obtained for 99.99% aluminium are 106 lines/sq. cm., 107 lines/sq. cm., and 108 lines/sq. cm. for well annealed crystals, for laminar regions of 10% elongated crystals, and for deformation bands of 10% elongated crystals, respectively.
