In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via i...In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via its AE features,including buckling,delamination incubation and spallation.According to the Fourier transformation of AE signals,there arefourdifferentfailuremodes：surfaceverticalcracks,opening and sliding interface cracks,and substrate deformation.The characteristic frequency of AE signals from surface vertical cracks is 0.21 MHz,whilst that of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.The energy released of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.Based on the energy released from cracking and the AE signals,a relationship is established between the interface crack length and AE parameters,which is in good agreement with experimental results.展开更多
Photon emission during contact electrification(CE)has recently been observed,which is called as CE-induced interface photon emission spectroscopy(CEIIPES).Physical mechanisms of CEIIPES are essential for interpreting ...Photon emission during contact electrification(CE)has recently been observed,which is called as CE-induced interface photon emission spectroscopy(CEIIPES).Physical mechanisms of CEIIPES are essential for interpreting the structure and electronic interactions of a contacted interface.Using the methods of density functional theory(DFT)and time-dependent DFT(TDDFT),it is confirmed theoretically that the spectrum of emitted photons is contributed from electron transfer and transition during CE.Specifically,the excited electrons from higher energy state in one material may transfer to a lower energy state of another material followed by a transition;and/or some unstable excited electrons at a higher energy level of one material may transit to a lower energy state of itself,both of which result in CEIIPES.Furthermore,the CE-induced interface absorption spectrum(CEIIAS)has been demonstrated,due to the intermolecular electron transfer excitation.展开更多
基金supported by the National Natural Science Foundation of China (Grants 11472237,11002122,51172192,and 11272275)
文摘In this paper,acoustic emission（AE） and digital image correlation methods were applied to monitor interface cracking in thermal barrier coatings under compression.The interface failure process can be identifie via its AE features,including buckling,delamination incubation and spallation.According to the Fourier transformation of AE signals,there arefourdifferentfailuremodes：surfaceverticalcracks,opening and sliding interface cracks,and substrate deformation.The characteristic frequency of AE signals from surface vertical cracks is 0.21 MHz,whilst that of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.The energy released of the two types of interface cracks are 0.43 and 0.29 MHz,respectively.Based on the energy released from cracking and the AE signals,a relationship is established between the interface crack length and AE parameters,which is in good agreement with experimental results.
基金supported by the National Natural Science Foundation of China(Nos.62001031,52192610,51702018,and 51432005)the Youth Innovation Promotion Association,CAS,the Fundamental Research Funds for the Central Universities(No.E0E48957)the National Key R&D Program from Minister of Science and Technology(No.2016YFA0202704).
文摘Photon emission during contact electrification(CE)has recently been observed,which is called as CE-induced interface photon emission spectroscopy(CEIIPES).Physical mechanisms of CEIIPES are essential for interpreting the structure and electronic interactions of a contacted interface.Using the methods of density functional theory(DFT)and time-dependent DFT(TDDFT),it is confirmed theoretically that the spectrum of emitted photons is contributed from electron transfer and transition during CE.Specifically,the excited electrons from higher energy state in one material may transfer to a lower energy state of another material followed by a transition;and/or some unstable excited electrons at a higher energy level of one material may transit to a lower energy state of itself,both of which result in CEIIPES.Furthermore,the CE-induced interface absorption spectrum(CEIIAS)has been demonstrated,due to the intermolecular electron transfer excitation.
