Once Again about the Nature of Martensite Formation in Iron and Steels

I. M. Laptev, O. O. Parkhomenko

National Science Center ‘Kharkiv Institute of Physics and Technology’, NAS of Ukraine, 1 Akademichna Str., UA-61108 Kharkiv, Ukraine

From the standpoint of the method of phase diagrams of martensitic transformations (PDMF), an analysis of the literature data, obtained experimentally and theoretically in the study of martensitic transformations in carbon steels, is performed starting from the 20s of the last century and ending with modern works. In accordance with the PDMF, it is impossible to consider polymorphic phase transformations (including martensitic ones) without taking into account the participation of vacancies in them. Just vacancies are the connecting link that unites volume, deformations, and stresses into a single whole. A comparison of the known data on the changes in the crystal lattice parameters of austenite, ferrite, and martensite allow us to conclude that, during the formation of a martensitic crystal, carbon simply shifts in all cells along the edge of the quenching stress that is favourably oriented relative to the current gradient. In this case, the tetragonality of martensite in carbon steels is determined not by carbon, but by vacancy-carbon complexes, which arise as a result of, for example, quenching. A scheme for determining the waves of concentration inhomogeneities in carbon steels is proposed, which made it possible to construct the dependence of the temperatures of martensitic transformations ($M_s$ and $M_f$) on the carbon concentration. Based on these constructions, it was shown that martensite cannot contain carbon more than 1% wt. The PDMF method allows dividing the process of martensite formation into two stages. The first stage is the formation of elastic ‘austenitic’ martensite ($\gamma^{'}$-phase) by shear during cooling. The crystal is deformed until the $\gamma^{'}$-phase remains stable. The second stage is the loss of stability, the isolation of the crystal and its transformation into a ‘ferritic’ ($\alpha^{'}$-phase) martensite. The second stage is a quantum mechanical phenomenon, since the process is caused by a change in interatomic bonds. The process proceeds instantly, with a simply shift and at a constant temperature.

Key words: crystal structure, phase transformation, martensite, carbon steel, tetragonality, vacancies, stress.

URL: http://mfint.imp.kiev.ua/en/abstract/v42/i11/1583.html

DOI: https://doi.org/10.15407/mfint.42.11.1583

PACS: 61.50.Ks, 61.66.Dk, 61.72.Bb, 61.72.Dd, 61.72.S-, 81.30.Kf

Citation: I. M. Laptev and O. O. Parkhomenko, Once Again about the Nature of Martensite Formation in Iron and Steels, Metallofiz. Noveishie Tekhnol., 42, No. 11: 1583—1599 (2020) (in Ukrainian)

REFERENCES
1. M. M. Steinberg, J. Tekhn. Fiz., 5, No. 2:362 (1935) (in Russian).
2. A. P. Guliaev, Metallovedenie [Metal Science] (Moscow: Oborongiz: 1963) (in Russian).
3. S. P. Oshkaderov, Uspehi Fiziki Metallov, 12: 269 (2011) (in Russian). Crossref
4. A. G. Khachaturian, Teoriya Fazovykh Prevrashcheniy i Struktura Tverdykh Rastvorov [The Theory of the Phase Transformation and Solid Solution Structure] (Moscow: Nauka: 1974) (in Russian).
5. Yu. N. Koval and V. A. Lobodyuk, Deformatsionnye i Relaksatsionnye Yavleniya pri Prevrashcheniyakh Martensitnogo Tipa [The Deformation and Relaxation Phenomena under Martensitic Transformation] (Kyiv: Naukova Dumka: 2010) (in Russian).
6. Yu. J. Meshkov, Proc. of Int. Conf. 'The Modern Problems of the Metal Physics and Metallic Systems' (May 25-27, 2016) (Kyiv: IMF N.A.S.U.: 2016) (in Russian).
7. E. E. Kaminskiy and M. D. Perkas, Problemy Metallovedeniya i Fiziki Metallov [The Metal Science and Physics of Metal Problems] (Moscow: Metallurgy: 1949), p. 211 (in Russian)
8. M. P. Arbuzov, Sbornik Nauchnykh Rabot Laboratorii Metallofiziki AN USSR 'Voprosy Fiziki Metallov i Metallovedeniya', No. 6 (Kyiv: N.A.S.U.: 1955) (in Russian).
9. G. V. Kurdyumov, Yavleniya Zakalki i Otpuska Stali [The Quenching and Aging of Steel Phenomena] (Moscow: Metallurgiya: 1960) (in Russian).
10. G. V. Kurdyumov, L. M. Utevsky, and R. I. Entin, Prevrashcheniya v Zheleze i Stali [Transformations into Iron and Steels] (Moscow: Nauka: 1977) (in Russian).
11. G. V. Kurdyumov and L. I. Lisak, J. Techn. Fiz., 19, No. 2: 525(1949) (in Russian).
12. V. A. Lobodyuk and Yu. Ya. Meshkov, Metallofiz. Noveishie Technol., 39, No. 9: 1281 (2017) (in Russian). Crossref
13. I. N. Laptev and A. A. Parkhomenko, East European Journal of Physics, 4, No. 3: 92 (2017) (in Russian).
14. O. P. Morozov, D. A. Mirzaev, and M. M. Steinberg, Fizika Metallov i Metallovedenie, 32, No. 6: 1290 (1971) (in Russian).
15. A. Damask and J. Diens, Tochechnye Defekty v Metallakh [Point Defects in Metals] (Moscow: Mir: 1966) (in Russian).
16. N. Ya. Rokhmanov, I. N. Laptev, I. P. Onishenko, and O. O. Parkhomenko, Functional Materials, 13, No. 2: 255 (2006).
17. V. A. Lobodyuk and Yu. J. Meshkov, Metallofiz. Noveishie Tekhnol., 42, No. 1: 123 (2020) (in Russian). Crossref
18. G. V. Kurdyumov and A. G. Khachaturyan, Acta Metallurg., 23, No. 9: 1077 (1975). Crossref
19. I. N. Laptev and A. A. Parkhomenko, Uspehi Fiziki Metallov, 11: 19 (2010) (in Russian). Crossref
20. I. N. Laptev and A. A. Parkhomenko, Vakansii, Martensytni Peretvorennya i Resurs Yadernykh Reaktoriv [Vacancies, Martensitic Transformation, and Nuclear Reactors Life Time] (Kharkiv: 2018) (in Ukrainian).