Inelastic constitutive equation of plasma-sprayed ceramic thermal barrier coatings
来源期刊：Acta Metallurgica Sinica2011年第2期
论文作者：Masayuki ARAI
文章页码：161 - 168
摘 要：Ceramic thermal barrier coatings （TBCs） are a very important technology for protecting the hot parts of gas turbines （GTs） from a high-temperature environment. The coating stress generated in the operation of GTs brings cracking and peeling damage to the TBCs. Thus, it is necessary to evaluate precisely such coating stress in a TBC system. We have obtained a stress-strain curve for a freestanding ceramic coat specimen peeled from a TBC coated substrate by conducting the bending test. The test results have revealed that the ceramic coating deforms nonlinearly with the applied loading. In this study, an inelastic constitutive equation for the ceramic thermal barrier coatings deposited by APS is developed. The obtained results are as follows: （1） the micromechanics-based constitutive equation was formulated with micro crack density formed at splat boundary, and （2） it was shown that the numerical results for a nonlinearly deformed beam simulated by the developed constitutive equation agreed with the experimental results obtained by cantilever bending tests.
Masayuki ARAI
Materials Science Research Laboratory, Central Research Institute of Electric Power Industry
摘 要：Ceramic thermal barrier coatings （TBCs） are a very important technology for protecting the hot parts of gas turbines （GTs） from a high-temperature environment. The coating stress generated in the operation of GTs brings cracking and peeling damage to the TBCs. Thus, it is necessary to evaluate precisely such coating stress in a TBC system. We have obtained a stress-strain curve for a freestanding ceramic coat specimen peeled from a TBC coated substrate by conducting the bending test. The test results have revealed that the ceramic coating deforms nonlinearly with the applied loading. In this study, an inelastic constitutive equation for the ceramic thermal barrier coatings deposited by APS is developed. The obtained results are as follows: （1） the micromechanics-based constitutive equation was formulated with micro crack density formed at splat boundary, and （2） it was shown that the numerical results for a nonlinearly deformed beam simulated by the developed constitutive equation agreed with the experimental results obtained by cantilever bending tests.
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