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Please use this identifier to cite or link to this item: http://apo.ansto.gov.au/dspace/handle/10238/4698

Title: Defect dynamics in polycrystalline zirconium alloy probed in situ by primary extinction of neutron diffraction
Authors: Kabra, S
Yan, K
Carr, DG
Harrison, RP
Dippenaar, RJ
Reid, M
Liss, KD
Keywords: STEELS
PHASE TRANSFORMATIONS
EVOLUTION
ZIRCONIUM
THERMAL RECOVERY
HEATING
Issue Date: 14-Feb-2013
Publisher: American Institute Physics
Citation: Kabra, S., Yan, K., Carr, D. G., Harrison, R. P., Dippenaar, R. J., Reid, M., & Liss, K. D. (2013). Defect dynamics in polycrystalline zirconium alloy probed in situ by primary extinction of neutron diffraction. Journal of Applied Physics, 113(6), Article Number 63513.
Abstract: After alpha+beta-zirconium has fully transformed into beta-phase upon heating, the intensities of all beta-Zr Bragg reflections decrease simultaneously as a function of time. It is shown that this effect represents a transition from the kinematic to the dynamic theory of diffraction due to the ever increasing crystal perfection driven by thermal recovery of the system. The best fitting coherent crystallite size of 30 mu m and other microstructural features are verified by in situ laser scanning confocal microscopy. This effect of primary extinction in neutron diffraction has been employed to further investigate the crystal perfection kinetics. Upon further heating, crystal recovery is identified as a process of dislocation annihilation, suffering from lattice friction. Upon cooling, precipitating alpha-Zr induces strain into the perfect beta-crystallites, re-establishing the kinematic diffraction intensities. An Avrami analysis leads to the estimations of nucleation time, consumption of nucleation sites and lower-dimensional growth. Such technique bears great value for further investigation on all metal systems annealed close to the melting temperature. © 2013, American Institute of Physics.
URI: http://dx.doi.org/10.1063/1.4790177
http://apo.ansto.gov.au/dspace/handle/10238/4698
ISSN: 0021-8979
Appears in Collections:Journal Articles

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