Determination of special boundary coordination at quadruple nodes using EBSD

Abstract

Grain boundaries are known to play an important role in materials properties including corrosion and cracking resistance. Some grain boundaries are resistant to corrosion and cracking and are known as "special" boundaries. While the structure of individual grain boundaries is important, the connectivity of the grain boundaries largely determines the properties of a bulk material. The coordination and connectivity of special grain boundaries have previously been studied in two dimensional grain boundary networks and are quantified by the triple junction distribution (TJD), which has been found to be non-random. The study of connectivity has been extended to three dimensions and simulations have previously been done to obtain a quadruple node distribution (QND) which was also non-random. Using Electron Back-Scattered Diffraction to characterize grain boundaries in copper and aluminum, this project obtains an experimental quadruple node distribution and verifies that it too is non-random.