Damage resistance of a thermal barrier coated superalloy used in aero turbine blade under accelerated creep condition
2009 (English)In: High Temperature Materials and Processes, Vol. 28, no 1-2, 35-53 p.Article in journal (Refereed) Published
This paper highlights the hot tensile and accelerated creep properties of a thermal barrier coated (TBC) AE 437A alloy used as a candidate blade material in aero engines. Acoustic emission technique has been utilised to characterise the ductile-brittle transition temperature of the bond coat. Results revealed that the DBTT (ductile to brittle transition temperature) of this bond coat is around 923 K, which is in close proximity to the value reported for NiCoCrAlY type of bond coat. Finite element technique used for analysing the equivalent stresses in the bond coat well within the elastic limit, revealed highest order of equivalent stress at 1073 K as the bond coat is ductile above 923 K. The lifetime of the TBC coated superai loy was superior to that of the bare substrate and that oxidation is likely the cause of the reduced life of the bare substrate as compared to the coated substrate while stress rupture or accelerated creep experiments are carried out in an oxidizing environment.. Delamination of the bond coat and that of the TBC at high stresses during accelerated creep was evident. During accelerated creep, the mode of fracture in the substrate at very high stresses was transgranular whereas that at low stresses was intergranular.
Place, publisher, year, edition, pages
2009. Vol. 28, no 1-2, 35-53 p.
Creep, Finite element, Fractography, Intergranular, Spallation, Substrate, Tensile, Thermal barrier coating, Trans-granular, A-thermal, Acoustic emission techniques, Aero-engine, Bond coats, Close proximity, Coated substrates, Coated superalloys, Creep conditions, Creep properties, Damage resistance, Ductile-brittle transition temperature, Ductile-to-brittle transition temperature, Elastic limit, Equivalent stress, Finite element techniques, High stress, Hot tensile, Low stress, Mode of fracture, NiCoCrAlY, Oxidizing environments, Stress rupture, Transgranular, Turbine blade, Acoustic emissions, Finite element method, Fracture mechanics, Inorganic coatings, Spalling, Substrates, Superconducting transition temperature, Textures, Thermoelectricity, Turbomachine blades, Thermal barrier coatings
IdentifiersURN: urn:nbn:se:hv:diva-8505ISBN: 03346455 (ISSN)OAI: oai:DiVA.org:hv-8505DiVA: diva2:859916