Failure analysis of a gripping assembly loaded at temperatures above 1000 °C

0506332 - ÚFM 2020 RIV GB eng J - Journal Article
Luptáková, Natália - Dymáček, Petr - Jarý, Milan - Záležák, Tomáš
Failure analysis of a gripping assembly loaded at temperatures above 1000 °C.
Engineering Failure Analysis. Roč. 96, FEB (2019), s. 384-393. ISSN 1350-6307. E-ISSN 1873-1961
R&D Projects: GA MŠMT(CZ) LQ1601
Institutional support: RVO:68081723
Keywords : Creep testing machine * Grips * Superalloy * Oxidation * Creep
OECD category: Materials engineering
Impact factor: 2.897, year: 2019
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S1350630716307798?via%3Dihub

The aim of the present work was to study the high-temperature behavior of a Ni-15Cr-18Co-4Al-3.5Mo powder-processed polycrystalline superalloy. This superalloy has been used to make the gripping assembly of a new commercial creep testing machine up to 1200 °C. The gripping assembly was exposed to a temperature of 1100 °C for 10 days at a nominal stress of 0.3 MPa and a local peak stress of 3.5 MPa. During this creep test, unacceptable creep deformation of the gripping assembly occurred. Three states of the superalloy microstructure were studied: (i) the state at receipt, (ii) the heat-treated state (annealing, 1200 °C/10 min/air), and (iii) the state following its use as a gripping assembly adapter during the creep test. Microstructural degradation resulted from exposed γ′ phase face-centered cubic Ni 3 Al particles that were preferentially created at the grain boundaries. Uniaxial tensile creep tests were conducted at 870 °C over a range of applied stresses from 100 to 220 MPa, and two tests were performed at 1000 °C and 1100 °C at 100 MPa and 10 MPa, respectively. A rapid drop in both the creep strength and the oxidation resistance was observed above 1000 °C. After deformation, the microstructure was investigated using advanced SEM and TEM techniques. Based on this investigation, the studied material is not recommended for use in creep testing machine gripping assemblies at temperatures above 1000 °C.
Permanent Link: http://hdl.handle.net/11104/0297719