抄録
Multiplication processes of dislocations in thick foils are continuously observed by high-voltage electron microscopy. When an applied stress reaches a certain value, which is lower than the apparent yield stress, some segments of grown-in dislocations existing on a single slip plane become active in proportion to their length. Each of them emits 10∼20 dislocations through the Frank-Read mechanism. Pole-dislocations of them, however, are also moved out with increase of the stress. These processes are closely related to cross-slip. With increase of the stress, main process of multiplication is switched to that of double cross-slip type, whose source number increases exponentially with increasing the stress. This stage is responsible to the apparent yield phenomenon. Besides these, generation of dislocations at stress-concentrated parts, such as voids, crack tips so on, are also continuously observed.
