[seminar] Seminar na IF-u, 16. travnja 2015. u 16:00h

[Niksa Krstulovic]

Institut za fiziku, Bijenička cesta 46, 

predavaonica u zgradi Mladen Paić četvrtak, 16. travnja 2015., u 16:00 sati 

Physical properties and mechanical behaviour of neutron-irradiated FeCr alloys 

Dr. Milan J. Konstantinovic 

Belgian nuclear institute, SCK•CEN, Boeretang 200, 2400 Mol, Belgium 



High Cr alloys and steels are candidate structural materials for the construction of several components of both fusion and fission reactors of next generation, because they are expected to be more resistant to irradiation than austenitic steels, while offering better thermal and thermo-mechanical properties. The high Cr ferritic steels are also known to be resistant to corrosion to exhibit reduced swelling and accumulated damage. Moreover, their composition can be tailored to reduce significantly their activation when subjected to neutron irradiation. 

The analysis of the correlation between the mechanical behaviour and physical/microstructural properties of various neutron irradiated FeCr alloys with different Cr concentrations is performed on the basis of extensive defect characterization utilizing various complementary techniques. The focus is given to the understanding of synergy between vacancy (and self interstitial), carbon and Cr atoms. It is found that the formation and properties of these complex defect structures are governed by initial microstructure and neutron irradiation conditions, causing different spatial distribution of these complexes. The defect distribution in the lattice is shown to be crucial for the mechanical behaviour of these alloys, providing plausible explanation of the difference between hardening and embrittlement. 

High Cr alloys also show interesting magnetic properties. Namely, diffuse neutron scattering and resistivity measurements revealed the existence of a change of sign of the short-range order parameters at the chromium concentration of about 9-10%. This spectacular band effect occurs due to peculiar thermodynamics and magnetic properties of Fe-Cr alloys. The magnetic interactions in FeCr alloys with the chromium content around 9-10% are believed to correspond to a perfect magnetically frustrated system, since Cr atoms interact antiferromagnetically with Fe and with the other Cr atoms. The relevance of this effect to the defect formation in FeCr alloys is also discussed. 

Voditelji seminara IF-a: Nikša Krstulović i Osor Bari šić 





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Nikša Krstulović, PhD 
Research associate 

Institute of Physics 
Bijenicka 46 
HR-10000 Zagreb, Croatia 

Phone: 00385 1 4698 872 
00385 1 4698 851 
Fax: 00385 1 4698 889 

http://www.ifs.hr/ 
http://spectra.ifs.hr/ 
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