Europhys. Lett., 58 (2) , pp. 243-249 (2002)
Long-range atomic order in irradiatedL. D. Cussen1, 2, 3, E. MacA. Gray4, A. P. Murani1, S. J. Kennedy3 and B. A. Hunter3
1 Institut Laue-Langevin - 6 Rue Jules Horowitz, B.P. 156 X Grenoble Cedex 9, France
2 Victoria University of Technology - P.O. Box 14428, MCMC 8001, Australia
3 ANSTO - PMB 1, Menai NSW, 2234, Australia
4 School of Science, Griffith University - Brisbane 4111, Australia
(Received 12 July 2001; accepted in final form 25 January 2002)
Atomic short-range order is commonly observed in alloys via a diffuse ( ) peak in neutron diffraction patterns. There has been speculation for many years on the existence and nature of any corresponding long-range order. A sample of has been irradiated in a high fast-neutron flux to produce a large number of crystal defects at around room temperature and thus facilitate the ordering process. Measurements of the diffuse neutron scattering from this sample demonstrate that long-range order has been induced in the sample, as evidenced by at least five Bragg peaks. This order is not seen in a reference sample prepared in identical fashion except for the irradiation. The Cowley short-range order parameters for both samples are calculated and a candidate structure for the long-range order is proposed.
61.50.Ks - Crystallographic aspects of phase transformations; pressure effects.
61.72.Ji - Point defects (vacancies, interstitials, color centers, etc.) and defect clusters.
61.80.Hg - Neutron radiation effects.
© EDP Sciences 2002