The Zener Relaxation in Some High Purity Iron-Vanadium Alloys

Abstract

R6sum6.-La relaxation de Zener a Bte CtudiQ dans trois alliages Fe-V de haute purete, contenant 12, 16 et 20 % en poids de vanadium. Les mesures ont Bt6 faites en pendule de torsion inverse, sous vide, dans une gamme de frequence allant de 0,l a 10 Hz. Les temps de relaxation (rr), dans le domaine de temperature 650-720 OC, peuvent dtre represent& par les equations suivantes Fe-12 % V zr = 1.1 x 10-22 exp(93,500/RT) Fe-16 % V 7, = 1.6 x 10-23 exp(95,500/RT) Fe-20 % V 7, = 1.9 x 10-24 exp (96,70O/RT). On suppose l'existence d'une relation entre les paramgtres de relaxation (7% et AHr) et les parametres de diffusion correspondant au mecanisme le plus rapide ; il a kt6 trouvk que les vitesses de diffusion croissent avec le pourcentage de vanadium. Les resultats sont discutks B partir des theories habituelles de la relaxation de Zener et l'on donne des explications pour les hautes energies d'activation du processus de diffusion.

Zener relaxations in the FeCo alloy system

“…The anomalously small value of zo in the two dilute alloys is more difficult to interpret. Seraphim [6] reported even smaller zo values (1.9 x 10-24) in the Fe-V system which was associated with an activation energy much higher than that for normal self diffusion. They attributed this phenomenon to the influence of ferromagnetic spin ordering on the activation energy.…”

“…The high values of activation energy and low values of t o associated with the 23.1 and 30.3 wtyo Co alloys require more explanation. The reason for these [6] when investigating Fe-V alloys. At temperatures between 600 and 800 "C the zo values they found were very small (2: s) and were associated with activation energies much higher than those for normal diffusion at temperatures above 800 "C. This effect was attributed to the influence of ferromagnetic spin ordering on the activation energy for diffusion.…”