From single defects to a structure-property relationship for polycrystals

The challenge confronting the microscopist seeking to elucidate the connection between the properties and microstructure of a polycrystalline material or the engineer seeking to design a material is immense. This is because of the diversity of interface structure and the complexity of the interactions possible between the various defects in interfaces and in the grain interiors. It is argued that so far the defects observed in interfaces seldom provide a mechanism for interfacial processes and that existing experimental approaches are fundamentally limited to a subset of the totality of interfaces which may be formed. However, to establish a structure-property correlation for a polycrystalline material as distinct from a bicrystal it may not be necessary to have a detailed knowledge of structure for each individual interface. Instead, a differentiation of interfaces into a limited number of classes each with distinctive properties which can be analysed utilising the insights of percolation may provide the means to connect the properties of individual interfaces to the behavior of the polycrystalline ensemble. © 1992.