ISSN:
1013-9826
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:
A surface strain measurement approach to understanding of delamination processes of thermal barrier coatings (TBCs) under heat cycle conditions was described in this paper. Heat cycle tests between the high temperature ranged from 1473K to 1073K and the relatively low temperature (573K) was carried out on thermal barrier coated type 304 stainless steel specimens. 8mass%Y〈sub〉〈/sub〉2O〈sub〉〈/sub〉3-ZrO〈sub〉〈/sub〉2 and Al〈sub〉〈/sub〉2O〈sub〉〈/sub〉3 coatings were used for the TBCs. The surface strain behavior during the heat cycle test was measured using a laser speckle strain/displacement gauge (SSDG). It was found that the thermal expansion of a substrate was almost reflected on a surface strain if a delamination wasn't initiated, while the value of a surface strain decreased to the value of the thermal expansion of a ceramics-coating if the delamination of the ceramics-coating was initiated. The state of a subsurface delamination was able to be nondestructively inferred by the surface strain behavior. The delamination life of a ceramics-coating in the specimen with a low-pressure-plasma-sprayed (LPPS)bond-coating was found to be longer than that with an atmospheric-plasma-sprayed (APS) bond-coating. The large roughness of a bond-coating was also found to be effective in improving the delamination life of a ceramics-coating owing to the restriction of a crack propagation parallel to the interface between the ceramics-coating and the bond-coating
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/47/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.261-263.453.pdf
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