In situ optical microscopic recording of slip line development during plastic deformation of Cu-15at%Al single crystals with high resolution--estimation of dislocation velocities.

Abstract

Observations and measurements of slip line evolution during plastic deformation are performed by optical microscopic video recording. In addition, high resolution in time is achieved by means of photodiodes positioned in the intermediate image plane of the microscope. Examples of measurements at room temperature on short-range ordered Cu-15at%Al single crystals are given and evaluated to estimate the velocities of edge and screw dislocation groups from the observed rates of growth of slip steps in height and in length, respectively, on one side of the specimen. By means of a second microscope observing the opposite side, the average rates for the dislocations to cross the whole specimen can be obtained. The measured values are discussed in terms of the movement of correlated dislocation groups in the crystals.