Precipitates as Internal Markers for High Temperature Deformation Studies

A problem in the study of high temperature deformation mechanisms such as grain boundary sliding or diffusion creep is to obtain good metallographic evidence to demonstrate the probable occurrence of such processes. The difficulty arises because marked changes in microstructure such as those commonly observed after dislocation creep, e.g. grain elongation, sub-grain formation, changes in dislocation distribution, are not usually associated with sliding and diffusion creep so that microstructural comparisons before and after deformation are not too informative. Surface markers are frequently used as an indication of relative grain sliding and rotation, but there are separate difficulties in relating these observations to bulk behaviour.