The application of a hot deformation SEM stage, backscattered electron imaging and EBSD to the study of thermomechanical processing

摘要

The technique of combining in situ hot-deformation and high resolution electron backscattered diffraction (EBSD) has been applied to study the mechanisms operating during the thermomechanical processing of metals. A simple hot tensile-straining stage is installed in a field emission gun scanning electron microscope equipped with an EBSD system and has been used successfully for a number of preliminary investigations. These investigations include substructure formation, dynamic subgrain and grain growth, superplastic deformation in aluminium alloys, and dynamic recrystallization in copper. Despite the surface topography, which inevitably increases during plastic deformation, channelling contrast backscattered electron micrographs have been successfully obtained after strains of up to similar to50%. Good quality EBSD maps have been obtained after strains of up to 100%. Most observations and measurements from the in situ experiments are consistent with what is known about the mechanisms occurring in the bulk. The microstructures revealed in the centre of the in situ samples after later repolishing are generally similar to those at the surface. [References: 11]