Dislocation densities in slowly cooled aluminium single crystals

Abstract

The dislocation density of slowly cooled, zone-refined aluminium single crystals, made by the strain-anneal method, has been studied, using Lang's x-ray diffraction topography technique. Three supplies of aluminium were used. The dislocation density in crystals from two of the supplies was found to be approximately linear to the cooling rate, and it was 2 × 10² lines per cm² for the slowest cooling rate, 2°c per hour. Three crystals were re-annealed, heated and cooled at a rate of 4°C per hour with maximum temperature 510°c, and topographs of these crystals reveal both increases and decreases in dislocation density.