Calorimetric studies of the enthalpies of formation of alloys from Ni₇₅Al₂₅-Ni₇₅Cr₂₅ and Ni₇₅Al₂₅-Ni₈₅Cr₁₅ sections at 873 K

• Autorzy: Maciąg T. , Rzyman K.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The main purpose of the study was to determine value of formation enthalpy ΔfH of Ni3Al-based alloys with chromium additions at temperature 873 K. Experiment was carried in order to determine the course of phase boundaries γ’ / γ’+ γ / γ for Ni-Al-Cr system. Design/methodology/approach: Experiment was performed with use of high temperature solution calorimeter. This “in situ” method allows to determine formation enthalpy in a wide range of temperature thanks to intermediate multi socket container which was applied in the device. It is fundamental because keeping the structure of examined alloys during quenching is extremely difficult, often impossible in this type of alloys. Findings: Distinct breaks in the course of enthalpy of formation ΔfH as a function of chromium concentration were discovered, that are assigned to courses of γ’ / γ’+ γ / phase boundaries. Research limitations/implications: Experiment will be proceeded at higher temperatures and completed with resistometric measurements. All results will be used in CAPLHAD procedure in order to optimize course of phase boundaries. Originality/value: The results are valuable thermodynamic data and method proposed can become a new way of direct determination of phase boundaries in metallic systems.

Słowa kluczowe

EN

metallic alloys; intermetallic phases; solution calorimetry; formation enthalpy

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2012
• Tom: Vol. 55, nr 2
• Strony: 275--279
• Opis fizyczny: Bibliogr. 15 poz., rys., tab.

Twórcy

autor

Maciąg T.

• Department of Metallurgy, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice, Poland

autor

Rzyman K.

• Department of Metallurgy, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice, Poland

Bibliografia

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• [9] N. Saunders, A.P. Miodownik, CALPHAD - Calculation of Phase Diagrams, A Comprehensive Guide, Pergamon, 1998.
• [10] P. Broz, R. Picha, J. Bursik, Phase equilibria calculations in the Ni-Al-Cr-Co and Ni-Al-Cr-W systems with respect to new experimental information on the gamma and gamma phase region, Proceedings of the XXXI Calphad Conference, Grenoble, 1999.
• [11] N. Dupin, I. Ansara, B. Sundman, thermodynamic re-assesment of the ternary system Al-Cr-Ni, Calphad 25/2 (2001) 279-298.
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• [14] K. Rzyman, J.-C. Gachon, Formation enthalpy of AlNi3-based alloys with iron additions by calorimetric solution and direct reaction methods, Archives of Metallurgy and Materials 55 (2010) 1021-1028.
• [15] M. Ellner, K.J. Best, H. Jacobi, K. Schubert, Struktur von Ni3Ga4, Journal of the Less Common Metals 19/3 (1969) 294-296 (in German).