Diffusion in three different dislocations in an fcc crystal

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Abstract
A theoretical study is made of dislocation pipe self‐diffusion in an fcc crystal for three differing dislocation structures to ascertain the correlation factor, diffusivity, and mobility in an electric field. The three structures may be described as a pure edge dislocation with the usual Burgers vector b=a/2[110]. The other two are mixed dislocations with b=a[01̄0] and either a line sense of ξ=a[100] or ξ=a[101]. The latter two are similar to an edge‐type dislocation and are formed by the removal of one‐half of a (010) plane of atoms whose edge follows these directions. It is found that very little difference exists in the transport processes in these three structures. Thus, although the latter two dislocations have a major screw character in the sense of a mixed dislocation, the transport is dominated by the edge character which in turn is controlled by the binding energy of the vacancy to the core. Additionally, the ratio of the mobility to diffusivity in an electric field is proportional to the reciprocal of the correlation factor as found in the past for other self‐diffusion situations, and these authors conclude that such a result is an unprovable axiom of correlated crystalline transport.