ELECTRON MICROSCOPIC OBSERVATION ON THE DISLOCATION CONFIGURATION CORRELATIVE WITH THE HIGH-TEMPERATURE INTERNAL-FRICTION PEAK IN 99.999 wt % SINGLE-CRYSTAL ALUMINIUM

Abstract
The dislocation structure in sheet specimens of 99.999 wt % aluminium single crystals was observed by transmission electron microscope (TEM) in order to explore the micromechanism corresponding to the appearance and disappearance of the internal-friction peak around 365°C (f = 1 HZ). /1/ Internal-friction measurements were made with an inverted torsion pendulum on sheet specimens having a thickness of 1 mm or smaller and a width of 4.5 mm. The same specimen was thinned down after the internal-friction measurements by chemical polishing and a double jet electrolytic polishing to films about 700 nm thick for TEM observations. The results of internal-friction measurements were compared with TEM observations.