Interfacial toughness evaluation of thermal barrier coatings by bending test  

作　　者：Qi Zhu Wei He Lei Chen Jianguo Zhu Wenfeng Hao 

机构地区：[1]Department of Mechanics and Science Engineering,Jiangsu University [2]AML,Department of Engineering Mechanics,Tsinghua University

出　　处：《Theoretical & Applied Mechanics Letters》2018年第1期3-6,共4页力学快报（英文版）

基　　金：financial support from the National Natural Science Foundation of China(11232008,11372118,and 11672345);the Natural Science Foundation of Jiangsu Province(BK20161341);the Six Talent Peaks Project in Jiangsu Province(2016-HKHT-004)

摘　　要：Determining the interfacial properties of thermal barrier coatings(TBCs) is imperative for their durability evaluation and further improvements. A ceramic coating(topcoat) and a NiCoCrALY bondcoat were atmospheric-plasma-sprayed(APS) on a stainless steel substrate. A modified three-point bending test was adopted to initiate and propagate the topcoat/bondcoat(TC/BC)interfacial crack. After a complete delamination, the fracture surfaces were examined by an optical microscope, which shows that the cracking plane was merely on the TC/BC interface. Based on the experimental results of load–displacement and crack length–displacement,the strain energy release rate G for crack propagation was calculated, and the averaged magnitude was 77.1 J/m^2.Repeatable results have indicated that the method can be used for the evaluation of interfacial fracture toughness in thermal barrier coatings and other multi-layer structures.Determining the interfacial properties of thermal barrier coatings(TBCs) is imperative for their durability evaluation and further improvements. A ceramic coating(topcoat) and a NiCoCrALY bondcoat were atmospheric-plasma-sprayed(APS) on a stainless steel substrate. A modified three-point bending test was adopted to initiate and propagate the topcoat/bondcoat(TC/BC)interfacial crack. After a complete delamination, the fracture surfaces were examined by an optical microscope, which shows that the cracking plane was merely on the TC/BC interface. Based on the experimental results of load–displacement and crack length–displacement,the strain energy release rate G for crack propagation was calculated, and the averaged magnitude was 77.1 J/m^2.Repeatable results have indicated that the method can be used for the evaluation of interfacial fracture toughness in thermal barrier coatings and other multi-layer structures.

关 键 词：Thermal BARRIER coatings Three-point BENDING INTERFACIAL FRACTURE TOUGHNESS 

分 类 号：O3[理学—力学]