Research on interfacial fracture behavior of TBCs/Q345 based on local approach

The critical load at crack propagation for the coated specimens was obtained through the tensile test, and the finite element method(FEM) was conducted to simulate the fracture behavior by ABAQUS code.Then the results from FEM were input into a self-programmed FORTRAN code, the two parameters of Weibull distribution dominating the interfacial fracture were obtained.The mathematical formula of the local approach applied to analyze the interface fracture was deduced.After that, the local approach was adopted to analyze the crack-size dependence of coating specimens for interface brittle fracture initiation.It was found that the Weibull stress for all specimens is almost identical under the same fracture probability when the interface fracture initiation occurs for different crack-size specimens.Moreover, the interface fracture behavior of one type of specimens with crack can be predicted from the test results of the other type of pre-crack specimens based on the local approach, and the predicted results have a good agreement with the test results.It showed that the local approach not only can be used to describe the interface fracture behavior, but also can be used in the integrity evaluation for interface between different materials.