Grain Maps and Grain Dynamics — A Reconstruction Challenge

Tuesday, January 10, 2006 - 9:45am - 10:30am
EE/CS 3-180
Henning Poulsen (Technical University of Denmark)
Crystalline materials such as most metals, ceramics, rocks, drugs, and bones are composed of a 3D space-filling network of small
crystallites r the grains. The geometry of this network governs a range of physical properties such as hardness and lifetime before
failure. Our group has pursued an experimental method r 3DXRD r which for the first time enable structural characterisation of the
grains in 3D. Furthermore, changes in grain morphology can be followed during typical industrial processes such as annealing or

3DXRD is based on reconstruction principles. In comparison to conventional tomography the use of higher dimensional spaces is
required. The projections are subject to group symmetry and their number is inherently limited. The grains exhibit a number of
geometric properties which can be utilised. Furthermore the problem at hand can be reformulated in terms of both vector-type and
scalar-type reconstructions. In conjunction these effects make 3DXRD reconstruction mathematically challenging.

The 3DXRD method will be presented with a few applications. The algorithms developed so far r for simplifying cases r will be
summarised with focus on continuous reconstruction methods.
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