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M: Metallphysik

M 18: Postersitzung

M 18.11: Poster

Dienstag, 9. März 2004, 14:30–16:30, Saal C

Resistometric investigations of "order-order" kinetics in intermetallics with varying superstructure stability — •Ewa Partyka and Rafal Kozubski — M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland

Investigations of long - range ordering kinetics in ternary intermetallic systems of superstructure L1₂ were carried out. Two groups of compounds: Ni₇₅Al_25−xFe_x and Pt₇₅Co_25−xFe_x , showing opposite relationships between the stability of L1₂ superstructure and concentration of Fe, were examined by means of isochronal residual resistivity.

The effect has been analyzed within the Schulze- Lücke formalism [1] enabled separate estimation for vacancy formation E_F and migration E_M energies being components of the overall activation energy E_A for ordering kinetics. It was found out that in both systems an increase of activation energy E_A accompanying an increase of L1₂ superstructure stability is due the increasing tendency of the vacancy formation energy E_F, the activation energy for vacancy migration E_M shows either week decrease with x (Pt₇₅Co_25−xFe_x) or no Fe-concentration dependence (Ni₇₅Al_25−xFe_x).

References:
Schulze A, Lücke K. Acta Metall 1972;20:529.