Interfaces in Materials

Much of materials science and engineering is played out at the level of a material's microstructure. From a more refined perspective, the quest to tune or create new microstructures may also be thought of as a series of exercises in interfacial control. Indeed, interfaces in materials are the seat of an extremely wide variety of processes ranging from the confinement of electrons to the fracture of polycrystals. The character of the interfaces that populate a given material leaves an indelible imprint on that material's properties. Whether we consider the susceptibility of a given material to chemical attackat its surfaces, the transport properties of complex semiconductor heterostructures, or the fracture of steels, ushered in by the debonding of internal interfaces, ultimately, interfaces will be seen as one of the critical elements yielding a particular material response. In some cases, the presence of such interfaces is desirable, in others, it is not. In either case, much effort attends the ambition of controlling such interfaces and the properties that they control.

Until this point in the book we have concerned ourselves with defects of reduced dimensionality. The present chapter aims to expand that coverage by turning to two-dimensional wall defects. The analysis of these defects will serve as our jumping off point for the consideration of microstructures within materials.