Short-Range Order Kinetics in Fe-Cr Alloys

Postgraduate Thesis uoadl:1318662 347 Read counter

Unit:
Κατεύθυνση Φυσική των Υλικών (ΒΑΣΙΚΗ ΦΥΣΙΚΗ)
Library of the School of Science
Deposit date:
2014-01-20
Year:
2014
Author:
Λουκιάνοβα Βικτόρια
Supervisors info:
Γ. Αποστολόπουλος, Ερευνητής Β', ΕΚΕΦΕ «ΔΗΜΟΚΡΙΤΟΣ», Γ. Αποστολόπουλος, Αναπλ. Καθηγητής ΕΚΠΑ, Ε. Συσκάκης, Επίκ. Καθηγητής ΕΚΠΑ
Original Title:
Μελέτη της κινητικής της τάξης μικρής εμβέλειας στο κράμα Fe-Cr
Languages:
Greek
Translated title:
Short-Range Order Kinetics in Fe-Cr Alloys
Summary:
Ordering phenomena play an important role in the phase stability of metallic
alloys. During service, alloy materials may be subjected to varying external
conditions. Their stability during these variations will depend also on the
rapidity with which a specific state of order can be established. In the
present work the kinetics of short-range ordering (SRO) are studied for the
first time in the Fe-Cr system, in the temperature range 700-950K. Fe-Cr alloys
are of special technological importance since they form the base of ferritic
stainless steels, which appart from their supperior corrosion and chemical
resistance are currently also considered as structural materials for advanced
nuclear applications as, e.g., the future fusion power reactors. Electrical
resistivity measurements were used to determine changes of SRO. A special
experimental device was constructed for performing annealing and quenching
cycles inside a liquid He dewar. The study has shown that in Fe-Cr an increase
in SRO leads to an increase of the residual resistivity, hence it may be
classified as a “K-state” alloy. Furthermore, the SRO relaxation time was found
to obey an Arrhenius behavior with activation energy of E=3.4±0.2eV. The
observed activation energy for SRO relaxation was correlated with the
activation energy for Cr diffusion.
Keywords:
Ordering phenomena, Short-range order kinetics, Electrical resistivity measurments, Fe-Cr alloys, Activation energy
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
36
Number of pages:
70
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