Creep fracture ductility of cobalt-based superalloys

0534028 - ÚFM 2021 RIV CH eng C - Conference Paper (international conference)
Kvapilová, Marie - Král, Petr - Dvořák, Jiří - Sklenička, Václav
Creep fracture ductility of cobalt-based superalloys.
Proceedings of the First International Conference on Theoretical, Applied and Experimental Mechanics. Cham: Springer Nature, 2019 - (Gdoutos, E.), s. 184-189. Structural integrity, 5. ISBN 978-3-319-91989-8. ISSN 2522-560X. E-ISSN 2522-5618.
[ICATEM - First International Conference on Theoretical, Applied and Experimental /1./. Paphos (CY), 17.06.2018-20.06.2018]
R&D Projects: GA MPO FV10699
Institutional support: RVO:68081723
Keywords : Cobalt based superalloys * creep fracture mode * damage tolerance zone
OECD category: Materials engineering

The challenge and demands of environmental protection and energy saving have been more and more serious tasks in some processing technologies of glass industry. Significant effort is being carried out for the development of advanced technology for precision casting of spinner discs for glass industry (glass wool) and high temperature applications up to 1050 °C. In this paper a study creep facture processes of two different cobalt-based superalloys Co Stelit and Co Ursa Stelit was investigated. Constant load uniaxial stress creep tests in tension were carried out at three different testing temperatures of 900 °C, 950 °C and 1000 °C and at the applied stress ranging from 40 to 200 MPa. A mutual comparison of the creep characteristics of the investigated alloys under comparable creep loading conditions shows that the cobalt based superalloy co Stelit exhibits more brittle character of fracture than superalloy Co Ursa Stelit. By contrast, the values of time to fracture (creep life) are longer for the superalloy Co Stelit in comparison to those for superalloy Co Ursa Stelit. The analyses of creep data indicate that creep behaviour of the superalloys under investigation obey both Monkman-Grant and its modified version. The creep fracture modes of these superalloys were determined using empirical formulas based on a continuum damage mechanics approach. The values of damage tolerance factor gamma correspond to mixture of transgranular and intergranular type of fracture of both superalloys.
Permanent Link: http://hdl.handle.net/11104/0312268