Observation of Structure Evolution During Annealing of 7xxx Series Al Deformed at High Temperature

Abstract

Deformation of polycrystalline materials results in a heterogeneous distribution of dislocation structures that are dependent upon the local character of the microstructure. 7xxx series aluminum alloys are particularly complex because of the wide range of particles and solute atoms that are in the material. High temperature deformation results in a microstructure that may be essentially free from dislocation structures at one position but have relatively high dislocation content at another position. Electron backscatter diffraction was used to quantify and map the dislocation density tensor at various positions through the metal. Subsequent annealing resulted in the development of recrystallization nuclei that were also observed by EBSD and related to the measured dislocation structure.