Papers by Author: A.W. Larsen

Abstract: A critical point in the understanding of recrystallization textures is the development of crystallographic orientations of the nuclei. Here an issue, which has been debated much recently [eg. 1], is if nuclei have orientations identical to those of the deformation microstructures from which they originate or not. Traditional nucleation mechanisms like strain induced boundary migration [2] and particle stimulated nucleation [3] operate with nuclei orientations identical to the “parent”deformation microstructure. This is also what is commonly incorporated in recrystallization modeling. However, a number of studies have found recrystallization nuclei in orientations that were not expected from measurements on deformed structures. Some of these results are reviewed and discussed in this paper, and new in-situ results obtained by the 3 dimensional X-ray diffraction (3DXR) method are presented.

Abstract: Possible variations in recrystallization kinetics from the sample surface to the center have been investigated in 90% homogeneously cold rolled aluminium (AA1050). It was found that whereas the average growth rates are quite similar, the nucleation characteristics are different at the surface and in the bulk.

Abstract: A new method for in-situ studies of nucleation in bulk metals based on high energy synchrotron radiation is presented. Copper samples cold rolled 20% are investigated. The crystallographic orientations near triple junctions are characterized using non-destructive 3DXRD microscopy before, during, and after annealing for 1 hour at 290°C. This method allows in-situ identification of new nuclei and the deformed material, which spawns the nuclei. Also, since data is acquired during annealing nucleation kinetics can be studied.