Critical Mechanical Behavior Study Of SiCO-based Films System Based On XFEM

Silicon carbon oxygen(SiCO)film in lithium battery electrode and gas sensor,and other fields has a broad application prospect,and the reliability of the mechanical analysis and prediction is the key to its commercial application needs to solve problems,the key to Liz bowyer base film such as plasticity and fracture mechanics behavior research has not yet fully developed,and at present mainly adopts the nano-indentation testing technology in this research has some limitations.The finite element method can characterize the elastic-plastic stress distribution of materials,and the finite element simulation can provide a basis for the experiment,which can significantly improve the design efficiency of the material system.The extended finite element method can describe the crack growth process,and can obtain parameters such as energy release rate and fracture toughness through analysis,which is more advantageous for the study of thin-film matrix fracture.Based on extended finite element and nano-indentation simulation,the plastic behavior and fracture properties of SiCO films are evaluated and predicted.In order to improve the accuracy of the model,it is proposed to increase the interface layer to describe the mechanical behavior of the interface of different materials in the thin film system,and to fit the load displacement curve obtained from the experiment by constantly modifying the stress-strain relationship.The results show that the addition of the interface layer can obviously optimize the fitting precision of the load displacement curve in the interface area.On this basis,the system to SiCO/Si substrate nano-indentation simulation and analysis,the calculation obtained with different young's modulus of load displacement curve,SiCO film indentation process is calculated in different stages of the young's modulus,hardness and energy release rate was coincident with the experimental data,and succeeded in capturing the interface fracture mechanics behavior.By calculating the stress-strain relationship,yield strength and strength coefficient of the film system,the plastic characteristics of the film system are obtained,and the influence of different matrix on the mechanical behavior of the film is discussed.In addition,the mechanical behavior of SiCN/SiCO/SiCN/PEOX multilayer film system was studied,and the influence of changes in young's modulus of SiCN film and SiCO film on the interface strength of the film system was discussed.The energy release rate calculated at different indentation depths was consistent with the experimental results.