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Mathematical forecasting composition of secondary carbides in the single-crystal superalloys

Glotka O.A., Olshanetskii V.I.

Archives of Materials Science and Engineering

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2021

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Vol. 111, nr 1

34--41

EN

Purpose: Predicting the specifics of the distribution of alloying elements between secondary carbides, their topology, and morphology, as well as the composition for a single-crystal multicomponent system of the type Ni-11.5Cr-5Co-3.6Al-4.5Ti-7W-0.8Mo-0.06C using the calculated CALPHAD (passive experiment) versus scanning electron microscopy (active experiment). Design/methodology/approach: This work presents the results of studies of the distribution of chemical elements in the composition of carbides, depending on their content in the system. The studies were carried out using an electron microscope with computer analysis of images and chemical composition. Findings: It was found that the influence of alloying elements on the composition of carbides is complex and is described by complex dependencies that correlate well with the obtained experimental results. Research limitations/implications: An essential problem is the prediction of the structure and properties of superalloys without or with a minimum number of experiments. Practical implications: The obtained dependencies can be used both for designing new superalloys and for improving the compositions of industrial alloys. Originality/value: The value of this work is that the obtained dependences of the influence of alloying elements on the dissolution (precipitation) temperatures and the distribution of elements in secondary carbides in the superalloy of the Ni-11.5Cr-5Co-3.6Al-4.5Ti-7W- 0.8Mo-0.06C system. It was found that changes in the course of the curves of temperature dependence on the element content closely correlate with thermodynamic processes occurring in the system, that is, the curves exhibit extrema accompanying the change in the stoichiometry of carbides or the precipitation of new phases.

2

Thermodynamic approach to the development and selection of hardfacing materials in energy industry

Shihab Thaer, Prysyazhnyuk Pavlo, Semyanyk Iryna, Anrusyshyn Roman, Ivanov Olexandr, Troshchuk Lyubomyr

Management Systems in Production Engineering

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2020

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nr 2 (28)

84--89

EN

The overall study objection is selection and optimization all available thermodynamic data required for using calculation of phase diagram (CALPHAD) technique within the Fe-C-Cr-Mn-Si-Ti system. Such data collected in the thermodynamic database can be used for predicting the phase constitution states of a given composition for Fe-based hardfacing materials, which often use in energy industry in order to increase the abrasion and impact wear resistance of equipment parts. In order to compare theroretical calculation results with experimental data, four different types of hardfacing were deposited using flux-cored arc welding. Microstructure and chemical composition of deposited layers was investigated using optical and scanning electron microscopy together with energy dispersive X-ray spectroscopy. Comparison of experimental and computed results shows that they are in good agreement in meaning of presence of all-important phase equilibrium regions. The developed database can be used for rational selection of hardfacing materials for energy industry equipment and reasonable choice of new alloying systems.

3

Modelling the composition of carbides in nickel-based superalloys of directional crystallization

Glotka O. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 102, nr 1

5--15

EN

Purpose: The specifics of the influence of alloying elements on the chemical composition of various types of carbides, their topology and morphology for a multicomponent system of the type Ni-5Cr-9Co-6Al-1Ti-11.7W-1.1Mo-1.6Nb-0.15C using the calculation method CALPHAD. It is shown that the obtained dependences closely correlate with thermodynamic processes occurring in the system. Design/methodology/approach: This work presents the results of studies of the distribution of chemical elements in the composition of carbides, depending on their content in the system. Findings: It was found that the influence of alloying elements on the composition of carbides is complex and is described by complex. Research limitations/implications: An essential problem is the prediction of the structure and properties of heat-resistant alloys without or with a minimum number of experiments. Practical implications: The obtained dependences can be used both for designing new heat-resistant alloys and for improving the compositions of industrial alloys. Originality/value: The value of this work is that the obtained dependences of the influence of alloying elements on the dissolution (precipitation) temperatures and the distribution of elements in carbides in the alloy of the Ni-5Cr-9Co-6Al-1Ti-11.7W-1.1Mo-1.6Nb-0.15C.