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B2 order transformation in a Fe – 25 at% Co – 9 at% Mo alloy

  • Christoph Turk (a1), Gert Kellezi (a2), Harald Leitner (a2), Peter Staron (a3), Weimin Gan (a3), Helmut Clemens (a1) and Sophie Primig (a1)...


The ternary system Fe - 25 at% Co - 9 at% Mo shows an age hardening behavior similar to aluminum alloys. After solution annealing followed by rapid quenching, the Fe-Co-matrix is hardened during subsequent aging through precipitation of the intermetallic µ-phase (Fe,Co)7Mo6. In aged condition the entire Mo content is present in coarse primary and fine µ-phase particles and, therefore, the matrix consists exclusively of 71 at% Fe and 29 at% Co. The binary system Fe-Co shows a transformation from the disordered bcc structure to the ordered B2 structure between 25 and 72 at% Co at a critical ordering temperature ranging from room temperature to 723°C. As a consequence, the remaining overaged matrix in the Fe - 25 at% Co - 9 at% Mo system should also show such a transition. However, an ordered phase is brittle and, thus, not wanted for many applications. Better mechanical properties in terms of ductility can be achieved with a partially or fully disordered phase. Such a state can be obtained by rapid quenching from temperatures above the critical ordering temperature. In this study such an approach was implemented on the ternary Fe - 25 at% Co - 9 at% Mo alloy. The effect of different cooling rates on the mechanical properties was investigated by means of hardness testing. The actual ordering transition of the Fe - 29 at% Co matrix was determined with differential scanning calorimetry and neutron diffraction.



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1. Leitner, H., Schober, M., Clemens, H., Caliskanoglu, D., Danoix, F., Int. J. Mater. Res. 99, 367 (2008).
2. Sourmail, T., Prog. Mater. Sci. 50, 816 (2005).
3. Zhao, L., Baker, I., Acta Metall. Mater. 42, 1953 (1994).
4. Vyazovkin, S., Burnham, A. K., Criado, J. M., Pérez-Maqueda, L. A., Popescu, C., Sbirrazzuoli, N., Thermochim. Acta 520, 1 (2011).
5. Hofmann, M., Gan, W. M., Rebelo-Kornmeier, J., Schöbel, M., Neutron News 24, 14 (2013).
6. Gilles, R., Hofmann, M., Johnson, F., Gao, Y., Mukherji, D., Hugenschmidt, C., Pikart, P., J. Alloys Compd. 509, 195 (2011).
7. Yokoyama, T., Takezawa, T., Higashida, Y., Trans. Japan Inst. Met. 12, 30 (1971).
8. Asano, S. K. H., Bando, Y., Nakanishi, N., Trans. Japan Inst. Met. 8, 180 (1967).
9. Gomankov, V. I., Litvin, D. F., Loshmanov, A. A., Lyashchenko, B. G., Puzei, I. M., Sov. Phys.-Cryst. 7, 788 (1963).
10. Ohnuma, I., Enoki, H., Ikeda, O., Kainuma, R., Ohtani, H., Sundman, B., Ishida, K., Acta Mater. 50, 379 (2002).
11. Shull, C., Siegel, S., Phys. Rev. 75, 1008, (1949).
12. Mal’tsev, Y. I., Gorman’kov, V. I., Puzey, I. M., Skokov, A. D., Phys. Met. Met. 43, 47 (1977).
13. Gilles, R., Hofmann, M., Gao, Y., Johnson, F., Iorio, L., Larsen, M., Liang, F., Hoelzel, M., Barbier, B., Metall. Mater. Trans. A 41, 1144 (2009).



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