Copper Effect on Micro- and Nanostructures of Steels

Abstract:

Mechanical tests and electron microscopic structural studies of low-carbon copper-steels quenched after austenitization and tempered at different temperatures are carried out to clarify the decomposition mechanism of α-Fe based substitution solid solutions. With the onset of decomposition, limited nanosize (4–7 nm) precipitates of so-called ε-phase (solid solution of iron in copper with fcc structure) appear on dislocations. The substructure formed from the austenitic region during quenching determines the nature of such decomposition. In alloys with martensitic structure, the decomposition is heterogeneous. Both the formation of precipitates of the copper-rich ε-phase and their growth primarily occur on dislocations and grain boundaries. In supersaturated alloys with polyhedral ferrite structure, on the contrary, the decomposition is homogeneous, and the growth of the copper-rich phase occurs mainly in the defect-free part of the bcc matrix. Supersaturated iron begins to decompose, forming copper-rich zones isomorphic α-Fe. When a sufficiently high copper concentration is reached, these zones create mechanical stresses that cause local tetragonal distortions of the crystal lattice leading to its reconstruction. When a dislocation loop is formed around this zone, compensating for the elastic deformation, the coherence of the structure is destroyed and fcc precipitates are formed in the matrix. Satisfactory agreement between the theoretical estimate of 8 nm of the critical displacement required for the formation of a dislocation of inconsistency and the initial incoherent precipitates size determined experimentally – by electron microscopy, confirms the proposed mechanism based on the nucleation of nanoinclusions of the ε-phase copper in the bcc iron matrix.

• Periodical: Materials Science Forum (Volume 1161)
• Pages: 9-25
• DOI: https://doi.org/10.4028/p-wKojj7
• Online since: October 2025
• Authors: Teimuraz Berikashvili, Akaki Gigineishvili, Levan Chkhartishvili*
• Keywords: Copper Alloying, Decomposition, Mechanical Properties, Microstructure, Nanostructure, Quenching, Steel, Tempering

References

[1] S.G. Morozenko, B.E. Natapov, Effect of copper on the properties of steel R6M5, Met. Sci. Heat Treat. 32 (1990) 368-371.

DOI: 10.1007/bf00700047

[2] G. Fourlaris, A.J. Baker, Bainite formation in high carbon copper bearing steels, J. Phys. IV France C 7 (5) (1997) 389-394.

DOI: 10.1051/jp4:1997561

[3] A.M. Elwazri, A. Fatehi, J. Calvo, D. Bai, S. Yue, Analysis of copper effect on microstructures and mechanical properties in microalloyed steels, Iron Steel Inst. Japan Int. 48 (1) (2008) 107-113.

DOI: 10.2355/isijinternational.48.107

[4] E.J. Pavlina, S.-J. Lee, E.T. Virtanen, L.M. Rothleutner, Ch.J. van Tyne, Effects of copper on the hardenability of a medium-carbon steel, Metall. Mater. Trans. A 42 (2011) 3572-3576.

DOI: 10.1007/s11661-011-0906-6

[5] O.I. Sekunowo, S.I. Durowaye, O.P. Gbenebor, Effect of copper on microstructure and mechanical properties of construction steel, Int. J. Chem. Nucl. Metall. Mater. Eng. 8 (8) (2014) 785-789.

[6] A.A. Vnukov, Structure and properties of Fe–Cu–C system based sintered materials obtained using various alloying methods, Bull. Kharkiv Polytech. Inst. 49 (1158) (2015) 3-6. – in Russian

[7] V.I. Izotov, D.S. Ilyukhin, M.E. Getmanova, G.A. Filippov, Influence of copper on the structure and mechanical properties of pearlitic steels, Phys. Met. Metallog. 117 (6) (2016) 588-593.

DOI: 10.1134/s0031918x16040074

[8] T. Ogneva, N. Martyushev, I. Altpeter, M. Surkov, A. Tokarev, T. Krutskaya, Structure and properties of heat-treated medium-carbon steels alloyed with copper, Met. Working Mater. Sci. 20 (2) (2018) 130-143. – in Russian

DOI: 10.17212/1994-6309-2018-20.2-130-143

[9] P. Sellamuthu, P. Hodgson, N. Stanford, Effect of copper on microstructure, recrystallization and precipitation kinetics in strip cast low carbon steel, Mater. Res. Express 6 (2019) 1265j5 (1-20).

DOI: 10.1088/2053-1591/ab7310

[10] N. Saeidi, M. Raeissi, Promising effect of copper on the mechanical properties of transformation-induced plasticity steels, Mater. Sci. Technol. 35 (14) (2019) 1708-1716.

DOI: 10.1080/02670836.2019.1639889

[11] P. Maji, R.K. Bhogendro Meitei, S.K. Ghosh, Understanding the trends in welding of copper and steel, Univ. Porto J. Eng. 8 (6) (2022) 48-61.

[12] P. Salvetr, A. Gokhman, M. Svoboda, C. Donik, I. Podstranska, J. Kotous, Z. Novy, Effect of Cu alloying on mechanical properties of medium-C steel after long-time tempering at 500°C, Materials 16 (2023) 2390 (1-17).

DOI: 10.3390/ma16062390

[13] A. Huang, K. Wang, Y. Zhao, W. Wang, X. Wei, J. Peng, Effect of copper addition on the formability of 304L austenitic stainless steel, J. Mater. Eng. Perform. 32 (8) (2023) 3563-3570.

DOI: 10.1007/s11665-022-07367-2

[14] P. Lin, L. Wang, X. Liang, Q. Hu, L. Wang, Effects of copper infiltrant amount and infiltration method on mechanical properties of sintered steel, J. Phys. Conf. Ser. 2690 (2024) 012005(1-7).

DOI: 10.1088/1742-6596/2690/1/012005

[15] A.A. Gachechiladze, A.L. Oakley, B.G. Margiev, R.V. Chedia, L.S. Chkhartishvili, O.A. Tsagareishvili, Studying of process of obtaining nanocrystalline boron-containing alloys, Nano Studies 12 (2015) 205-208. – in Russian

DOI: 10.1016/b978-0-12-813351-4.00002-x

[16] A. Gachechiladze, B. Margiev, R. Chedia, A. Oakley, L. Chkhartishvili, O. Tsagareishvili, New nanoalloys for modifying the steel, in: J. Khantadze, L. Chkhartishvili, D. Ramazashvili, L. Tavadze (Eds.), Proc. 2nd Int. Conf. "Modern Technologies and Methods of Inorganic Materials Science", Sachino, Tbilisi, 2015, pp.228-231.

DOI: 10.1016/b978-0-12-813351-4.00002-x

[17] A. Oaklay, D. Macharadze, M. Ratishvili, B. Margiev, L. Chkhartishvili, Modification of chromium steel by nano-oxide composite, Proc. Georgian Natl. Acad. Sci. (Chem. Ser.) 42 (4) (2016) 516-519.

[18] A. Gachechiladze, A. Oakley, B. Margiev, O. Tsagareishvili, L. Chkhartishvili, M. Ratishvili, Some properties of nanoobjects and on modification of steel melts by nanocomposite, Nano Studies 13 (2016) 83-92.

[19] G. Zakharov, M. Chikhradze, D. Kvaskhvadze, N. Khidasheli, L. Chkhartishvili, G. Mikaberidze, S. Gvazava, Peculiarities of obtaining complex Fe–Mn–B ligatures by SHS-metallurgy technology using production wastes, ARPHA Proc. 7 (2024) 53-58.

DOI: 10.3897/ap.7.e0053

[20] T. Berikashvili, L. Chkhartishvili, A. Gigineishvili, Mechanism of ε-nanophase precipitation in copper-steel, in: L. Chkhartishvili, M. Chikhradze (Eds.), Abs. 7th Int. Conf. "Nanotechnology", Tech. Univ. Press, Tbilisi, 2024, pp.37-37.