Abstract
Single crystals of Cu-6.5 at%Si alloy having various orientations have been deformed in tension at room temperature and 77°K. In particular, the deformation of easy glide in the crystals oriented for single slip have been investigated by optical microscopy, replica and transmission electron microscopy. The results obtained are as follows.
(1) The plastic deformation of stage I occurs by a typical Lüders band-type propagation of the coarse slip bands. When the propagation is completed along the length of the crystal, stage I comes to an end and then stage II hardening appears.
(2) The slip band structure observed by replicas changes with deformation temperature. Spacing between slip bands at room temperature is wider than that at 77°K. On the other hand, step heights of slip bands coming most frequently at room temperature and 77°K are about 600 and 400 Å, respectively.
(3) The main feature of the dislocation structures in stage I is the arrangement of large groups of primary dislocation aligned in a single slip plane or in a few closely spaced neighbouring slip planes. Most of the dislocations lying on closly spaced neighbouring slip planes take a form of dipole clusters.
(4) During the easy glide, a few twin bands appear at the front region of Lüders band-type deformation; and it takes place on the primary slip plane.
