Papers by Author: David Saylor

Abstract: This paper describes some aspects of reconstruction of microstructures in three dimensions. A distinction is drawn between tomographic approaches that seek to characterize specific volumes of material, either with or without diffraction, and statistical approaches that focus on particular aspects of microstructure. A specific example of the application of the statistical approach is given for an aerospace aluminum alloy in which the distributions of coarse constituent particles are modeled. Such distributions are useful for modeling fatigue crack initiation and propagation.

Abstract: Measurements of the grain boundary character distribution in MgAl2O4 (spinel) as a function of lattice misorientation and boundary plane orientation show that at all misorientations, grain boundaries are most frequently terminated on {111} planes. Boundaries with {111} orientations are observed 2.5 times more frequently than boundaries with {100} orientations. Furthermore, the most common boundary type is the twist boundary formed by a 60° rotation about the [111] axis. {111} planes also dominate the external form of spinel crystals found in natural settings, and this suggests that they are low energy and/or slow growing planes. The mechanisms that might lead to a high population of these planes during solid state crystal growth are discussed.