Abstract
Co2V and Co3V alloys are used as examples to discuss the principles of creating modern phase diagrams to take into account the discovery of an ordering–separation phase transition in alloys. The results of electron-microscopic studies of the Co2V alloy after heat treatment at various temperatures are presented. A comparison of these results with the conclusions based on the existing Co–V phase diagram demonstrates their disagreement. This disagreement is explained in this work. It is concluded that the ordering–separation phase transition should be taken into account in plotting modern phase diagrams. The Fe–Cr and Ni–Cr phase diagrams are considered with allowance for the ordering–separation phase transition in them. A technique is described to determine the ordering–separation phase transition temperature by transmission electron microscopy. The introduction of the concept of the ordering–separation phase transition is shown to change the principles used by researchers to construct phase diagrams.
Similar content being viewed by others
References
J. P. Chevalier and W. M. Stobbs, “An electron diffraction study of short-range order in quenched Ni4Mo alloys,” Acta Metallurgica 24, 535–542 (1976).
J. Higgins, R. B. Nicholson, and P. Wilkes, “Precipitation in iron–beryllium system,” Acta Metallurgica 22, 201–217 (1974).
D. E. Laughlin and J. W. Cahn, “Spinodal decomposition in age-hardening Cu–Ti alloys,” Acta Metallurgica 23, 329–339 (1975).
L. A. Phillips and L. E. Tanner, “High-resolution electron microscopy observations on GP zones in an aged Cu–2 wt % Be crystal,” Acta Metallurgica 21, 441–448 (1973).
P. E. Flewitt, “Phase transformations in Nb 16 to 40% Zr alloys above the monotectoid temperature,” Acta Metallurgica 22, 47–63 (1974).
V. P. Izotov and L. M. Utevsky, “Structure of martensite crystals in a high-carbon steel,” Fiz. Met. Metalloved. 25, 98–110 (1968).
Yu. D. Tyapkin, I. Ya. Georgieva, V. A. Golikov, and V. A. Gulyaev, “Quasi-periodic structure of high-carbon martensite,” Dokl. Akad. Nauk SSSR 225, 335338 (1975).
M. Kusunoki and S. Nagakura, “Modulated structure of iron–carbon martensite studied by electron microscopy and diffraction,” Appl. Crystallogr. 14, 329–336 (1981).
B. P. J. Sandvik and C. M. Wayman, “Direct observation of carbon clusters in a high-carbon martensitic steel,” Metallography 16, 429447 (1983).
Y. Ustinovshikov, “‘Chemical’ phase transition in alloys: ordering–phase separation,” Cur. Opin. Solid State Mater. Sci. 14, 7–20 (2010).
Y. Ustinovshikov, “A new paradigm for metallic alloys in materials science,” Advanc. Mater. Phys. Chem. 5, 244–270 (2015).
Y. Ustinovshikov, M. Shirobokova, and B. Pushkarev, “Structural study of the Fe–Cr system alloys,” Acta Materialia 44, 5021–5032 (1996).
Y. Ustinovshikov, N. Lomova, and I. Shabanova, “High-temperature B2 ordering in Fe50Co50 alloy,” J. Phys. Chem. Solids 69, 1753–1757 (2008).
Y. Ustinovshikov and I. Shabanova, “Phase transitions in alloys of the Ni–Mo system,” Mater. Chem. Phys. 129, 975–980 (2011).
Y. Ustinovshikov, B. Pushkarev, and I. Igumnov, “Ferich portion of the Fe–Cr phase diagram: electron microscopy study,” J. Mater. Sci. 37, 2031–2042 (2002).
Yu. I. Ustinovshchikov and B. E. Pushkarev, “Sigma phase in an Fe50Co50 alloy,” Neorg. Mater. 46, 570573 (2010).
Yu. I. Ustinovshikov, “On the iron–carbon phase diagram,” Russ. Metall. (Metally), No. 5, 421–425 (2009).
I. N. Bogachev, Metallography of Cast Iron (GNTIL, Sverdlovsk, 1962)
Y. Aoki and J. Echigoya, “Phase separation in an 18.2 at % V–Co alloy annealed at 1073 K,” Scripta Metallurgica 19, 639–642 (1985).
Y. Ustinovshikov, “Phase transition ordering–phase separation in the Co3V alloy,” J. Alloys Comp. 639, 669–674 (2015).
Y. Ustinovshikov and I. Shabanova, “A study of microstructures responsible for the emergence of the invar and permalloy effects in Fe–Ni alloys,” J. Alloys Comp. 578, 292–296 (2013).
Y. Ustinovshikov, “Phase transition ‘ordering phase separation’ in the Ni–12 at % Al alloy,” J. Alloys Comp. 528, 141–145 (2012).
Y. Ustinovshikov, “Phase transformations in alloys of the Ni–Cr system,” J. Alloys Comp. 543, 227–232 (2012).
Y. Ustinovshikov, “Phase transition ‘ordering-phase separation’ in alloys of Ni–Cr system,” Mater. Chem. Phys. 165, 14–18 (2015).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © Yu.I. Ustinovshchikov, N.V. Kostenkov, 2017, published in Metally, 2017, No. 5, pp. 3–13.
Rights and permissions
About this article
Cite this article
Ustinovshchikov, Y.I., Kostenkov, N.V. Ordering–separation phase transition: The fate of the existing phase diagrams. Russ. Metall. 2017, 683–690 (2017). https://doi.org/10.1134/S0036029517090142
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0036029517090142