Statistics of twin-related domains and the grain boundary network

The twin-related domain, or a collection of contiguous grains related by twinning operations, is proposed as the basis for the analysis of grain boundary network connectivity in materials prone to annealing twinning. The distribution of the number of grains in a twin-related domain was measured for materials with a variety of compositions and processing histories. The Weibull distribution is found to accurately reflect many features of the twin-related domain populations, and the parameters of the Weibull distribution vary systematically with the number fraction of resistant boundaries in the microstructure. An alternative model based on the microstructural effects of sequential thermomechanical processing is proposed. This provides an overall fit to the experimental data of comparable quality to the Weibull distribution, while allowing an interpretation of the model parameters that suggests a refinement of the usual thermomechanical processing schedule.