Typical properties of grain boundaries are that they have higher thermal conductivity than the surrounding material [161]. In addition, they can also have a higher melting point than the bulk material because there may exist some constellations (phase stages) where the grain boundary regions have higher thermal stability than the surrounding bulk-like material and can therefore act as a stabilizing element in the material structure [161]. If these stabilizing grain boundary elements are located in a material with a certain regular density, they mainly determine the behavior of high temperature regions.