Electrometallurgy Today, 2026, №02

2026 №02 (04)

DOI of Article
10.37434/sem2026.02.05

2026 №02 (06)

"Suchasna Elektrometallurgiya" (Electrometallurgy Today), 2026, 2, 39-51 pages

Intermetallics of the Fe–Al system: current understanding of structure, properties and applications

Yu.V. Kostetskyi^1,3, M.P. Naumenko¹, O.A. Rokytska^2,3

¹E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: y.kostetsky@paton.kiev.ua
²2Frantsevich Institute for Problems of Materials Science of NASU. 3 Omeliana Pritsaka Str., 03142, Kyiv, Ukraine
³National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Ukraine. 37 Prospect Beresteiskyi, 03056, Ukraine

Abstract
This paper summarizes the current state of knowledge on phase equilibria, microstructure, and mechanical and functional properties of Fe–Al alloys. Particular attention is given to the features of formation and thermal stability of the A2, Fe3Al (D03), and FeAl (B2) phases, as well as to the influence of ordering and defect structure on strength and ductility. The roles of vacancies, grain boundaries, and dislocations in the temperature dependence of yield strength, including anomalous strengthening effect, are analyzed. It is shown that alloying with Cr, Mo, W, V, Ni, B, Ti, Nb, and Si significantly affects high-temperature strength, corrosion resistance, grain-boundary cohesion, and increase in the ductility of Fe–Al intermetallics. The main application areas of Fe–Al alloys in high-temperature structural components, wear-resistant parts, coatings, and composite materials are outlined. A review of the literature indicates that the rational combination of alloying and modern processing technologies broadens the prospects for the practical use of Fe–Al intermetallics as a cost-effective alternative to conventional high-temperature alloys. 63 Ref., 1 Tabl., 7 Fig.
Keywords: iron-aluminides, phase equilibrium, ordered D03 and B2 phases, defect structure, anomalous strengthening, alloying, high-temperature strength, corrosion resistance

Received: 17.03.2026
Received in revised form: 04.05.2026
Accepted: 20.05.2026
Posted online: 27.05.2026

References

1. Palm, M., Stein, F., Dehm, G. (2019) Iron aluminides. Annual Review of Materials Research, 49, 297-326. https://doi.org/10.1146/annurev-matsci-070218-125911
2. Zamanzade, M., Barnoush, A., Motz, C. (2016) A review on the properties of iron aluminide intermetallics. Crystals, 6(1), 10. https://doi.org/10.3390/cryst6010010
3. McKamey, C.G. (1996) Iron aluminides. Physical Metallurgy and Processing of Intermetallic Compounds. Eds by N.S. Stoloff, V.K. Sikka. Boston, Springer, 351-391. https://doi.org/10.1007/978-1-4613-1215-4_9
4. McKamey, C.G., DeVan, J.H., Tortorelli, P.F. et al. (1991) A review of recent developments in Fe3Al-based alloys. J. of Materials Research., 6, 1779-1805. https://doi.org/10.1557/JMR.1991.1779
5. Deevi, S.C., Sikka, V.K. (1996) Nickel and iron aluminides: An overview on properties, processing, and applications. Intermetallics, 4(5), 357-375. https://doi.org/10.1016/0966-9795(95)00056-9
6. Vilardell, A.M., Cinca, N., Tarrés, E., Kobashi, M. (2022) Iron aluminides as an alternative binder for cemented carbides: A review and perspective towards additive manufacturing. Materials Today Communications, 31, 103335. https://doi.org/10.1016/j.mtcomm.2022.103335
7. Oleszak, D., Shingu, P.H. (1994) Mechanical alloying in the Fe-Al system. Materials Science and Engineering A., 181-182, 1217-1221. https://doi.org/10.1016/0921-5093(94)90834-6
8. Stein, F., Palm, M. (2007) Re-determination of transition temperatures in the Fe-Al system by differential thermal analysis. Praktische Metallographie, 98(7), 580-588. https://doi.org/10.3139/146.101512
9. Stoloff, N.S. (1998) Iron aluminides: Present status and future prospects. Materials Science and Engineering A., 258(1), 1-14. https://doi.org/10.1016/S0921-5093(98)00909-5
10. Morris, D.G., Muñoz-Morris, M.A., Llorca, J. (2003) Intermetallics - A basic overview. Intermetallics, 11(4), 413-422.
11. arXiv:2410.12486. https://arxiv.org/abs/2410.12486
12. Liu, C.T., George, E.P., Maziasz, P.J., Schneibel, J.H. (1998) Recent advances in B2 iron aluminide alloys: Deformation, fracture and alloy design. Materials Science and Engineering A., 258(1-2), 84-98. https://doi.org/10.1016/S0921-5093(98)00921-6
13. Rolink, G., Vogt, S., Sencekova, L. et al. (2014) Laser metal deposition and selective laser melting of Fe-28 at. % Al. J. of Materials Research, 29, 2036-2043. https://doi.org/10.1557/jmr.2014.131
14. Schaefer, H.E., Würschum, R., Sob, M. et al. (1990) Thermal vacancies and positron-lifetime measurements in Fe76.3Al23.7. Physical Review B., 41, 11869-11874. https://doi.org/10.1103/PhysRevB.41.11869
15. Wolff, J., Franz, M., Hehenkamp, T. (1997) Defect analysis with positron annihilation-applications to Fe aluminides. Mikrochimica Acta, 125, 263-268. https://doi.org/10.1007/BF01246194
16. Broska, A., Wolff, J., Franz, M., Hehenkamp, T. (1999) Defect analysis in FeAl and FeSi with positron lifetime spectroscopy. Intermetallics, 7, 259-267. https://doi.org/10.1016/S0966-9795(98)00098-3
17. Rieu, J., Goux, C. (1969) Etude du durcissement par trempe des alliages ordonnés Fe-Al de type L20. Mémoires Scientifiques de la Revue de Métallurgie, 66, 869-880.
18. Hasemann, G., Schneibel, J.H., George, E.P. (2012) Dependence of the yield stress of Fe3Al on heat treatment. Intermetallics, 21, 56-61. https://doi.org/10.1016/j.intermet.2011.09.005
19. Yang, Y., Baker, I. (1998) The influence of vacancy concentration on the mechanical behavior of Fe-40Al. Intermetallics, 6, 167-175. https://doi.org/10.1016/S0966-9795(97)00062-9
20. Čížek, J., Lukáč, F., Melikhova, O. et al. (2011) Thermal vacancies in Fe3Al studied by positron annihilation. Acta Materialia, 59, 4068-4078. https://doi.org/10.1016/j.actamat.2011.03.031
21. Stein, F., Schneider, A., Frommeyer, G. (2003) Flow stress anomaly and order-disorder transitions in Fe3Al-based alloys. Intermetallics, 11, 71-82. https://doi.org/10.1016/S0966-9795(02)00187-5
22. Nishino, Y., Ogawa, K., Tanaka, H. (2012) Internal friction study of vacancy hardening in B2 FeAl alloys. Solid State Phenomena, 184, 81-86. https://doi.org/10.4028/www.scientific.net/SSP.184.81
23. Morris, D.G., Muñoz-Morris, M.A. (2014) High-temperature creep of iron aluminide intermetallics. Encyclopedia of Thermal Stresses. Dordrecht, Springer, 2226-2236. https://doi.org/10.1016/j.ijplas.2007.09.001
24. George, E.P., Baker, I. (1998) Thermal vacancies and the yield strength anomaly of FeAl. Intermetallics, 6, 759-763. https://doi.org/10.1016/S0966-9795(98)00063-6
25. Guo, J.T., Jin, O., Yin, W.M., Wang, T.M. (1993) Discovery and study of anomalous yield strength peak in FeAl alloy. Scripta Metallurgica et Materialia, 29, 783-785. https://doi.org/10.1016/0956-716X(93)90226-I
26. Morris, D.G., Zhao, P., Muñoz-Morris, M.A. (2001) Influence of strain rate on the stress anomaly in Fe3Al. Materials Science and Engineering A, 297, 256-265. https://doi.org/10.1016/0921-5093(96)10180-5
27. Krein, R., Palm, M. (2007) Two-fold flow stress anomaly in L21-ordered Fe-Al-Ti alloys. Materials Science and Engineering A, 460-461, 174-179. https://doi.org/10.1016/j.msea.2007.01.020
28. Morgand, P., Mouturat, P., Sainfort, G. (1968) Structure et propriétés mécaniques des alliages fer-aluminium. Acta Metallurgica, 16, 867-875. https://doi.org/10.1016/0001-6160(68)90107-7
29. Morris, G., Gutierrez-Urrutia, I., Muñoz-Morris, M.A. (2008) High temperature creep behaviour of an FeAl intermetallic strengthened by nanoscale oxide particles. Inter. J. of Plasticity, 24I(7), 1205-1223. https://doi.org/10.1016/j.ijplas.2007.09.001
30. McKamey, C.G., Horton, J.A., Liu, C.T. (1989) Effect of chromium on properties of Fe3Al. J. of Materials Research, 4, 1156-1163. https://doi.org/10.1557/JMR.1989.1156
31. Schulson, E.M. (1996) Brittle fracture and toughening. Physical metallurgy and processing of intermetallic compounds, 56-94. https://doi.org/10.1007/978-1-4613-1215-4_3
32. Risanti, D., Deges, J., Falat, L. et al. (2005) Dependence of the brittle-to-ductile transition temperature on Al content. Intermetallics, 13, 1337-1342. https://doi.org/10.1016/j.intermet.2005.02.007
33. Krein, R, Schneider, A., Sauthoff, G., Frommeyer, G. (2007) Microstructure and mechanical properties of Fe3Al-based alloys with borides. Intermetallics, 15, 1172-1182. https://doi.org/10.1016/j.intermet.2007.02.005
34. Azmi, S.A., Michalcová, A., Sencekova, L., Palm, M. (2017) Microstructure and mechanical properties of Fe-Al-Nb-B alloys. MRS Advances, 2, 1353-1359. https://doi.org/10.1557/adv.2017.138
35. Kanno, N., Yoshimura K., Takata, N. et al. (2016) Mechanical properties of austenitic heat-resistant steel. Materials Science and Engineering A, 662, 551-563. https://doi.org/10.1016/j.msea.2016.03.038
36. Morris, D.G., Muñoz-Morris, M.A. (1999) Influence of microstructure on ductility of iron aluminides. Intermetallics, 7, 1121-1129. https://doi.org/10.1016/S0966-9795(99)00038-2
37. Park, B., Ko, S., Park, Y. (2000) Mechanical properties of Fe3Al intermetallic matrix composites. MRS Online Proceedings Library, 646, 324-328. https://doi.org/10.1557/PROC-646-N5.19.1
38. Baker, I. (2011) An overview of the mechanical properties of FeAl. MRS Proceedings, 1128. https://doi.org/10.1557/PROC-1128-U02-01
39. Michalcová, A., Sencekova, L., Rolink, G. et al. (2016) Laser additive manufacturing of iron aluminides. Materials & Design, 116, 481-494. https://doi.org/10.1016/j.matdes.2016.12.046
40. Jordan, J.L., Deevi, S.C. (2003) Vacancy formation and effects in FeAl. Intermetallics, 11, 507-528. https://doi.org/10.1016/S0966-9795(03)00027-X
41. Gaydosh, D.J., Nathal, M.V. (1990) Influence of testing environment on the room temperature ductility of FeAl alloys. Scripta Metallurgica et Materialia, 24(7), 1281-1284. https://doi.org/10.1016/0956-716X(90)90342-E
42. Baligidad, R.G., Radhakrishna, A., Datta, A., Rama Rao, V.V. (2001) Effect of molybdenum addition on structure and properties of high carbon Fe3Al-based intermetallic alloy. Materials Science and Engineering A, 313(1-2), 117-122. https://doi.org/10.1016/S0921-5093(01)00962-5
43. Vodičková, V., Švec, M., Hanus, P. et al. (2025) Microstructure and high-temperature strength of Fe-Al-Si(-Mo) alloys with refractory metal additives. JOM, 1568-1580. https://doi.org/10.1007/s11837-025-07907-w
44. Zhang, Z., Sun, Y., Guo, J. (1995) Effect of niobium addition on the mechanical properties of Fe3Al-based alloys. Scripta Metallurgica et Materialia, 33(12), 2013-2017. https://doi.org/10.1016/0956-716X(95)00437-Z
45. Park, N., Lee, S.-C., Cha, P.-R. (2018) Effects of alloying elements on the stability and mechanical properties of Fe3Al from first-principles calculations. Computational Materials Science, 146, 303-309. https://doi.org/10.1016/j.commatsci.2018.01.042
46. Kontis, P., Yusof, H.A.M., Pedrazzini, S. et al. (2016) On the effect of boron on grain boundary character in a new polycrystalline superalloy. Acta Materialia, 103, 688-699. https://doi.org/10.1016/j.actamat.2015.10.006
47. Metidji, N., Younes, A. (2022) Effects of boron, nickel and molybdenum content on the microstructure, mechanical behaviour and wear properties of FeAl alloy made by vacuum arc melting. Transactions of the Indian Institute of Metals, 75, 2691-2699. https://doi.org/10.1007/s12666-022-02639-w
48. Duquette, D.J. (1995) Corrosion of intermetallic compounds. Intermetallic Compounds, 965-975.
49. Balasubramaniam, R. (1996) On the role of chromium in minimizing room temperature hydrogen embrittlement in iron aluminides. Scripta Materialia, 34(1), 127-133. https://doi.org/10.1016/1359-6462(95)00495-5
50. Lee, J.W., Wu, C.C., Liu, T.F. (2004) The influence of Cr alloying on microstructures of Fe-Al-Mn-Cr alloys. Scripta Materialia, 50(11), 1389-1393. https://doi.org/10.1016/j.scriptamat.2004.02.040
51. Novák, P., Nová, K. (2019) Oxidation behavior of Fe-Al, Fe- Si and Fe-Al-Si intermetallics. Materials, 12(11), 1748. https://doi.org/10.3390/ma12111748
52. Khaple, S., Golla, B.R., Prasad, V.V.S. (2023) A review on the current status of Fe-Al based ferritic lightweight steel. Defence Technology, 26, 1-22. https://doi.org/10.1016/j.dt.2022.11.019
53. Emdadi, A., Yang, Y., Szyndler, J. et al. (2026) Highly printable Fe3Al intermetallic alloy. Metals, 16(1), 5. https://doi.org/10.3390/met16010005
54. Rojacz, H., Varga, M., Mayrhofer, P.H. (2025) High-temperature abrasive wear behaviour of strengthened iron-aluminide laser claddings. Surface and Coatings Technology, 496, 131585. https://doi.org/10.1016/j.surfcoat.2024.131585
55. Gomes, A.F., Santos, H.S., Seno, R. (2025) Laser cladding of iron aluminide coatings for surface protection in Soderberg electrolytic cells. Metals, 15(12), 1337. https://doi.org/10.3390/met15121337
56. Kołodziejczak, P., Bober, M., Chmielewski, T.M., Baranowski, M. (2025) Structure and selected properties of coatings deposited by arc spraying under inert atmosphere containing in situ fabricated Fe-Al intermetallic phases. Materials, 18(3), 646. https://doi.org/10.3390/ma18030646
57. Dosta, S., Clavé, G., Betancor-Cazorla, L. et al. (2025) Optimization of Fe3Al intermetallic cold gas spray coatings: Microstructural characterization. Surface and Coatings Technology, 504, 132032. https://doi.org/10.1016/j.surfcoat.2025.132032
58. Smorygo, O. et al. (2022) Metal foam-reinforced microporous FeAlOᵧ/FeAlₓ composites for catalytic applications. Materials Chemistry and Physics, 283, 126013. DOI: https://doi.org/10.1016/j.matchemphys.2022.126013
59. Guo, E., He, Y., Zhong, F. et al. (2024) Preparing high performance FeAl/Al2O3 coating as tritium permeation barrier. J. of Nuclear Materials, 599, 155261. https://doi.org/10.1016/j.jnucmat.2024.155261
60. Wen, F., Zhang, D., Wang, W. et al. (2024) Preparation and formation mechanism of Fe-Al coating on 316L stainless steel by pack cementation aluminizing. Chinese J. of Materials Research, 38(10), 759-767. DOI: https://doi.org/10.11901/1005.3093.2023.561
61. Li, Y., Barzagli, F., Liu, P. (2023) Mechanism and evaluation of hydrogen permeation barriers: A critical review. Industrial & Engineering Chemistry Research, 62, 15752-15773. https://doi.org/10.1021/acs.iecr.3c02259
62. Ertugrul, G., Emdadi, A., Härtel, S. (2025) Powder production and additive manufacturing of iron aluminide alloys using plasma ultrasonic atomization and laser-directed energy deposition. Additive Manufacturing Letters, 14, 100313. https://doi.org/10.1016/j.addlet.2025.100313
63. Rojacz, H., Piringer, G., Varga, M. (2023) Iron aluminides - A step towards sustainable high-temperature wear resistant materials. Wear, 523, 204754. https://doi.org/10.1016/j.wear.2023.204754

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Suggested Citation

Yu.V. Kostetskyi, M.P. Naumenko, O.A. Rokytska (2026) Intermetallics of the Fe–Al system: current understanding of structure, properties and applications. Electrometallurgy Today, 02, 39-51. https://doi.org/10.37434/sem2026.02.05