Distribution of grain boundaries in magnesia as a function of five macroscopic parameters Original Research Article

A semi-automated method has been used to measure all five macroscopically observable parameters of 4.1×106 boundary plane segments making up 5.4 mm2 of boundary area in a hot-pressed magnesia polycrystal. The observations allow a complete description of the distribution of crystal orientations, grain boundary misorientations, and the crystallographic orientations of grain boundary planes. Among the low misorientation angle grain boundaries, there is a preference for tilt boundaries, especially those with boundary plane normals in the <110> direction. At all fixed misorientations, there is a preference for boundaries with a boundary plane normal in the <100> direction. These boundaries are generally asymmetric and occur at least twice as frequently as the average boundary for each fixed misorientation.