The Effect of Long-Term Ageing on the Degradation of the Microstructure the Inconel 740h Alloy

M. Srokaa, A. Zielińskib, A. Śliwaa, M. Nabiałekc, Z. Kania-Pifczykb, I. Vaskovád aInstitute of Engineering Materials and Biomaterials, Silesian University of Technology, S. Konarskiego 18A, 44-100 Gliwice, Poland bInstitute for Ferrous Metallurgy, K. Miarki 12-14, 44-100 Gliwice, Poland cInstitute of Physics, Faculty of Production Engineering and Materials Technology, Częstochowa University of Technology, al. Armii Krajowej 19, 42-200 Częstochowa, Poland dFaculty of Materials, Metallurgy and Recycling, Technical University of Kosice, Letná 9, 042 00 Košice, Slovak Republic

Received: August 22, 2019; revised version November 19, 2019; in final form December 10, 2019

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The Inconel 740H alloy is used in the construction of pressure components of ultra-supercritical operating parameters. The paper presents the results of microstructure analysis after 1000 and 10 000 h ageing at 700 and 750°. Microstructure studies were made using scanning and transmission electron microscopy. Identification of precipitations was made using X-ray analysis of phase composition. The influence of ageing time on changes in microstructure and the precipitation process of the tested alloy were described. Presented research results are a material characteristic of new generation materials, which are used in the design of elements of pressure parts of boilers and diagnostics work during operation.

DOI:10.12693/APhysPolA.137.355 topics: Inconel 740H, microstructure, precipitations, annealing, austenite