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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:24 |
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Conference: Bucharest University Faculty of Physics 2016 Meeting
Section: Solid State Physics and Materials Science
Title:
Local Configurations and Specific Properties of Metastable Fe-Cr and Fe-Mo Ribbons under Thermal Treatments in Different Atmospheres
Authors:
Anda Elena STANCIU (1,2), Simona Gabriela GRECULEASA (1), Cristina BARTHA (1), Gabriel SCHINTEIE (1), Petru PALADE (1), Andrei KUNCSER (1,2), Aurel LECA (1,3), George FILOTI (1), Victor KUNCSER (1)
Affiliation:
1) National Institute for Materials Physics, P.O.Box MG-7, 077125, Bucharest-Magurele, Romania
2) Bucharest University, Faculty of Physics, 077125, Bucharest-Magurele, Romania
3) Politehnica University of Bucharest, Faculty of Electronics, Telecommunications and Information Technology, Bucharest, Romania
E-mail
anda.stanciu@infim.ro
Keywords:
Fe1-xCrx and Fe1-xMox ribbons, Mössbauer Spectroscopy, Thermal Analysis, atomic intermixing
Abstract:
Fe-Cr and Fe-Mo ribbons were prepared by melt-spinning and subsequently subjected to thermal treatments at temperatures up to 1200 oC under different atmospheres. The composition of the Fe alloying element was ranged around 11% which is the Cr content in the Eurofer steel seen as a valuable alternative for supports of plasma facing components in Tokamak fusion reactors. The effect of replacing Cr with a larger element of similar electronic configuration was considered. Structural investigations revealed the formation of body center cubic (BCC) Fe-Cr and Fe-Mo solid solutions in the as quenched samples and specific deviations from a Poisson-like atomic distributions in the annealed samples. Differential scanning calorimetry emphasized the occurrence of structural and magnetic transitions in Cr and Mo based alloys, respectively. Thermogravimetric measurements underscored He uptake in a larger extent in the case of Mo containing ribbons than in the Cr counterparts. The transmission Mossbauer spectra were analyzed with respect to changes in the local configuration of Fe atoms by resuming to the first coordination sphere where the significant contributions to the hyperfine field are related to a Fe atom surrounded by zero, one and two Cr or Mo neighbors. Specific gradual decreases of the hyperfine field with Cr/Mo addition were observed for both the as-quenched and annealed samples, depending also on the gas atmosphere during the heating. Annealing induces oxidation even in the presence of Ar protective atmosphere in the case of Fe-Mo ribbons, the oxidation degree being increased both with Mo concentration and annealing temperature. The annealing treatment at 1250 oC in He atmosphere induces oxidation for all compositions and concentrations. Besides, the formation of a Fe-Cr paramagnetic phase attributed to Cr atoms clusterization is favored, while in the case of Mo analogues, a wüstite phase is observed.
References:
1. G. Schinteie, S.G. Greculeasa, P. Palade, G.A. Lungu, C. Porosnicu, I. Jepu, C.P. Lungu, G. Filoti,V. Kuncser, J Nucl Mater., 457, 220-226 (2015).
2. V. Kuncser, P. Palade, G. Schinteie, S. G. Sandu, L. Trupina, G. A. Lungu, N. G. Gheorghe, C. M. Teodorescu, C. Porosnicu, I. Jepu, C. P. Lungu, G. Filoti, J Alloy Compound., 512, 199-206 (2012).
3. S.G. Greculeasa, G. Schinteie, P. Palade, G. Filoti, L. Trupina, G.A. Lungu, O. Crisan, V. Kuncser, Adv Alloy Compound., 1, 30-45 (2014).
4. A. Blachowski, K. Ruebenbauer, J. Zukrowski, J. Przewoznik, J Alloy Compound., 482, 23-27, (2009)
5. S.M. Dubiel, J. Cieslak, J. Zukrowski, Appl Surf Sci., 359, 526-532, (2015).
Acknowledgement:
This work was supported by the Romanian National Program, Core Program 2016 at NIMP and the European Community under the EUROFUSION contract EU-1 WPPFC-R as well as by the contract E11/2014.
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