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phase equilibiria in Fe-C(ce,La)systems

Masuma Mardani
Электронная почта
Институт экотехнологий и инжиниринга (ЭкоТех)
Кафедра металловедения цветных металлов (МЦМ)
ФИО научного руководителя
PHD Dr. Alexandra khvan
Академическая группа
Наименование тезиса
phase equilibiria in Fe-C(ce,La)systems



Favourable effects of rare-earth elements on the mechanical and other properties of steel have been widely mentioned in the literature. There are three main roles of rare-earth metals in steels: modification of inclusions, deep purifying steel and alloying. However, the mechanism of the influence of the rare-earth additions on the property of the steel is still not clear. Thus, investigations of the RE–Fe–C systems would have great practical importance for the steel industry. The goal of the present research is to study the phase equilibria in the Fe-C-{La,Ce} systems.

Information on the phase equilibria in the Fe-C-La system is absent. Phase equilibria in the Fe-C-Ce system were studied by Park et al. [1]. The partial liquidus projection and partial isothermal sections at 950 and 800°C for the Fe-CeFe2-Ce2C3-C region of the Fe-C-Ce system were constructed. However, the temperatures of the proposed invariant reactions were not measured. Authors [1] observed two ternary compounds Fe4Ce4C7 / Fe5Ce3C6 (t1) and Fe2Ce2C3 / FeCe3.67C6 (t2). Both compounds to form through solid state reactions. Recently, the phase equilibria in this system at crystallization were studied by us [2]. The liquidus and solidus projections for this system over the whole concentration range were constructed [2].

Phase equilibria in the Fe-C-La system at crystallization have been studied by us in first time. The liquidus and solidus projections and melting diagram in whole concentration region have been constructed. The liquidus surface of the Fe-C-La system is characterized by primary crystallization regions of phases (С) graphite, (γFe), (δFe), (aFe), βLaC2, La2C3, (βLa) and (γLa). In the solidus surface four three-phase fields are present: (βLaC2) + (γFe) + (C), (αFe) + (La2C3) + (La), (La2C3) + (βLaC2) + (γFe) and (γFe) + (La2C3) + (αFe).

Phase equilibria in the Fe-C-Ce system have been studied at 1100°C. The isothermal section of the Fe-C-Ce system in whole concentration region at 1100°C was constructed. The ternary compound Ce4Fe4C71) is present at this temperature and is in equilibrium with the phases (γFe), Ce2C3 and CeC2 forming three three-phase fields, namely t1 + (γFe) + (CeC2), t1 + (CeC2) + (Ce2C3) and t1 + (Сe2C3) + (γFe) and corresponding two-phase regions.

Scientific adviser - PhD.Alexandra Khvan

[1] H.K. Park, H.H. Stadelmaier, L.T. Jordan, Z. Metallkd. 73 (1982) 399–402.

[2] A.V. Khvan, I.V. Fartushna, M. Mardani, et. al. J. Alloys Compd. 651 (2015) 350-356.