PSI - Issue 30

Available online at www.sciencedirect.com Available online at www.sciencedirect.com Sci nceD rect Structural Integrity Procedia 00 (2020) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2020) 000–000

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Procedia Structural Integrity 30 (2020) 201–208

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Abstract The study of structural and phase changes and processes of destruction of heat-resistant nickel alloys is necessary to solve urgent problems of improving the serviceability and reliability of parts of the hot path of gas turbine installations, including under severe temperature and power operating conditions in the North. The purpose of this work is to study the high-temperature degradation of metal and the nature of operational failures of parts of the hot path (heat insert, blades) of gas turbine units operating in an extremely cold climate. Using the methods of optical, scanning and transmission electron microscopy the morphological changes were revealed in the strengthening γ '-phase and other symptoms of instability in structural state of the alloys from which the failed parts had been made. The insufficient level of structural stability of alloys in non-stationary operating conditions of gas turbine installations in the North which sharply increase the load on the parts is revealed. The degradation of alloys was developed in the depletion of the solid solution by the intermetallide phase, the softening of intermetallide particles by internal defects, the development of intra-grain porosity, and the weakening of grain boundaries by precipitates and pores. The fracture of the heat insert (made of a deformable nickel alloy) was realized by the creep mechanism, the fracture of the working blades (made of a casting alloy) – by the thermal fatigue mechanism. A limited resource of the studied parts is caused by the insufficient level of service properties for the considered operating conditions as well as error modes of the gas turbines caused the overheating of parts. The improving of materials for gas turbine installations in the North requires the adapted optimization of alloys compositions and the development of technologies for manufacturing parts taking into account operating conditions. © 2020 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) Metal degradation of thermally loaded elements of power plants during operation in the North Yakovleva S. P. a , Makharova S. N. a, *, Ptitsyna A.V. a a Larionov Institute of Physical-Techincal Problems of the North SB RAS, 1 Oktyabrskaya Street, Yakutsk, 677980, Russia Abstract The study of structural and phase changes and processes of destruction of heat-resistant nickel alloys is necessary to solve urgent problems of improving the serviceability and reliability of part of the h t path of gas turb ne installations, including under sev re temp rature and power operating conditio s in the North. The purpose f this work is to study the high-temperature degradation of m t l and the nature of operational failures of parts of t hot path (heat insert, blades) of gas turbine units operating in a extremely cold climate. Using the methods of optical, canning and transmission lectron microscopy the morphologic l cha ges we r vealed in the strengthening γ '-phase and other symptoms of i tabil ty in structural state of t alloys from which the fail d parts had been made. The insufficient level of structural tability of alloys in non-stationary operating conditions of gas turbine in tallations in th North which sharply increase the lo d on the part is revealed. The degradation of alloys w developed in the depletion of the solid solution by the int rm talli e phase, the softening of intermetallide particles by intern l f cts, the dev lopm nt of intra-grain p ros ty, and the w akening of gr in boundari s by precipitat s an pores. The fracture of the heat insert (made of a deformable nickel alloy) was realized by the creep mechanism, the fracture of the working blades (mad of a casting alloy) – by the thermal fatigue mech nism. A limited resource of t e studied parts is caused by the insufficient level of service properties for the considered op rati g conditions as well as error modes of the ga turbines ca sed the o erheating of parts. The improving f materials fo gas turbine installations in the North r quires the adapted optimization of alloys comp sitions and the development of technol gies for manufacturing parts taking into account operating conditions. © 2020 The Authors. Publish d by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Keywords: superalloy, structure degradation, intermetallide phase, thermal-fatigue failure, creep. IX Eurasian Symposium on the problems of strength and resource in low climatic temperatures (EURASTRENCOLD-2020) Metal degradation of thermally loaded elements of power plants during operation in the North Yakovleva S. P. a , Makharova S. N. a, *, Ptitsyna A.V. a a Larionov Institute of Physical-Techincal Problems of the North SB RAS, 1 Oktyabrskaya Street, Yakutsk, 677980, Russia Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors Keywords: superalloy, structure degradation, intermetallide phase, thermal-fatigue failure, creep.

* Corresponding author. Tel.: +8-914-821-5659. E-mail address: snmachar@yandex.ru * Corresponding author. Tel.: +8-914-821-5659. E-mail address: snmachar@yandex.ru

2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors 2452-3216 © 2020 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of the EURASTRENCOLD - 2020 guest editors

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the EURASTRENCOLD - 2020 guest editors 10.1016/j.prostr.2020.12.031