The distribution of misorientations and grain boundary planes in grain boundary engineered brass

In this paper we report the application of a five-parameter determination of grain boundary types to grain boundary engineered alpha-brass. The data are discussed particularly in terms of the distribution of boundary planes, and also with respect to the potential relationship between the planes distribution and the misorientation distribution. Approximately 20,000 grains comprised the total sample population, giving rise to more than 77,000 grain boundary line segments. This is the first time that the orientation of a large sample population of grain boundary planes has been measured in a grain boundary engineered material. The most important findings of the investigation were that the distribution of planes shows a prevalence of <110> tilt boundaries, especially asymmetric tilt types, and the presence of <111> twist boundaries. This distribution is a consequence of the low energy of these boundary types. Furthermore more than three-quarters of boundaries could be considered to be ‘potentially special’. The presence of these boundaries greatly fragmented the grain boundary network. This fragmentation is probably a key factor in the development of superior properties in a grain boundary engineered material.