ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
In situ observation of the mechanical failure behavior was conducted for different kinds ofthe plasma sprayed thermal barrier coating (TBC) systems by means of an optical microscopy underthe static loadings at room and elevated temperatures; as the fundamental aspect, in order to clarify thethermomechanical failure mechanism of TBC system in connection with various coatingcharacteristics. Mechanical tensile or compressive loading was applied progressively to the TBCspecimen by an axial loading mode.It was found that the failure behavior of TBC system depends strongly on the testing temperatureunder both the tensile and compressive loadings. At the elevated temperature which is higher than theductile-brittle transition temperature (DBTT) of metallic bond-coat (BC), in particular, the ceramictop-coat (TC) spallation can be prevented by virtue of the stress relief induced by the enhanced plasticflow in the BC layer. At the room temperature which is lower than the DBTT of BC, on the contrary,the TC spalling was inevitably induced, but the initiation site of TC spalling is closely related with themagnitude of local plastic deformation in the alloy substrate. Furthermore, an influence of thermallygrown oxides (TGO) layer developed at the TC / BC interface on the crack initiation and propagationbehavior was investigated in some detail
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.522-523.345.pdf
