ACTA

Kinetics of "order-order" Relaxations in Ni₃Al Studied by Computer Simulation

P. Oramus^a, R. Kozubski^a, M.C. Cadeville^b, V. Pierron-Bohnes^b and W. Pfeiler^c
^a Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
^b GEMME, I.P.C.M.S., 23 rue du Loess, 67037 Strasbourg, France
^c Institut für Materialphysik, Universität Wien, Strudlhofgasse 4, 1090 Wien, Austria

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The experimental investigations of "order-order" kinetics in Ni₃ Al-based L1₂-ordered intermetallic compounds revealed the relaxation curves composed of two parallel processes considerably differing in relaxation rates. A simple Ising-type model based on a vacancy mechanism of atomic jumps was used to carry the Monte Carlo simulations of long-range-order relaxations in a binary A₃B system with L1₂-type superstructure. The simulated relaxation curves fitted weighted sums of two exponentials with significantly different relaxation times. It was found out that the fast relaxation process is controlled by the dynamics of the minority B-atom jumps.

DOI: 10.12693/APhysPolA.96.153
PACS numbers: 05.50.+q, 05.20.Dd, 66.30.-h, 81.30.Hd