Papers by Author: Gregory Owen

Abstract: Iterative processing, involving sequential deformation and annealing, has been carried out on copper specimens with the aim of grain boundary engineering (GBE) them. The data have provided some interesting insights into the mechanisms of GBE. The results have demonstrated that development of a high proportion of Σ3s is beneficial to properties, as shown by improved strain-to-failure for the same strength. The proportion of Σ3s saturates at approximately 60% length fraction. Analysis of the data indicates that iterative processing is not always necessary for the development of beneficial properties, and it is further suggested that the condition of the starting specimen has a large influence on the subsequent microstructural development. The present, new data are also compared with previous research on copper where all five parameters of the grain boundary network population have been measured.

Abstract: Grain boundary engineering (GBE) has been carried out on copper and brass. A comparison of the resulting microstructure and grain boundary characteristics from the two specimens revealed that the brass specimen had approximately the same number fraction of Σ3s as the copper specimen (38%), but a lower number fraction of Σ9s and Σ27s and a markedly different microstructure. In the brass specimen twins were not incorporated into the grain boundary network, whereas in the copper specimen Σ3s replaced portions of the grain boundary network. These two mechanisms are discussed in detail.