- Startpagina tijdschrift
- Volume 13 (1994)
- Number 2 - Proceedings of the sixth European congr...
- Quantitative analysis of dislocation substructures
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Quantitative analysis of dislocation substructures
Abstract
Microstructural defects in materials are usually modelled in terms of point, fibre or surface processes in stochastic geometry. Dislocations are a typical example of fibre structure in metals. In addition to the dislocation density the arrangement of dislocations, described by the pair correlation function, is an important characteristic of the dislocation substructure which reflects a prior treatment of the material.
For an isotropic structure, the function can be approximated by the planar pair correlation function, obtained from TEM micrographs, i.e. from projections of thin foils of thickness t.
The computer program for PC AT was prepared using a graphic card for the estimation procedure. The circular probes with increasing radius were used to evaluate the pair correlation function. The method was used to investigate the dislocation substructure in Cr-Mo-V ferritic steel before and after irradiating.
In addition to that, the relation of a dislocation substructure to both homogeneously distributed precipitate particles and heterogeneously formed radiation-induced defects in ferritic reactor pressure steels was studied by means of the cross-correlation function. Applying this function to a couple of random fibre process X and a random point process Y of particles and defects, respectively, centroids, provides information on the relation between these processes.