1971 年 20 巻 215 号 p. 962-967
In the preceding study the tensile tests were made of the specimens of zinc single crystals with their angle φ larger than 30° of the tensil axis and the c-axis of the crystal under hydrostatic pressure up to 2000kg/cm2.
In the present study the specimens having the angle φ less than 30° have been subjected to the same experiment.
The results are summarized as follows:
(1) The specimen is cleaved on its basal plane when the environmental hydrostatic pressure is below the critical value.
(2) While the hydrostatic pressure enacts the part of compressive stress component to suppress the breakage of the crystal, the extent to which the breaking stress is enhanced varies diversely with the value of φ, the mode of plastic deformation, and the manner of chucking the specimen.
(3) No cleavage takes place in the crystal when the environmental pressure exceeds the critical value, and most of the specimens tend to slip on their basal planes. As the angle φ decreases, however, this primary slip is accompanied by such additional deformations as kink, twin and the secondary basal slip within the twin, and a necking is developed in the specimen.
(4) When the angle φ is extremely low such as less than 5°, the necking is developed without an active slip on the basal plane and the specimen is broken in a shear-type mode.