Influence of tensile pre-fatigue stress on residual strength of SiC/(PyC/SiC)2/SiC minicomposites

The tensile-tension fatigue behavior of minicomposite SiC/(PyC/SiC)2/SiC at room temperature was studied, and the residual mechanical properties of specimens were tested after 106 pre-fatigue cycles under different levels of stress. The results show that the residual strength first increases owing to the release of stress concentration and then decreases owing to excessive fiber wear. In addition, it is worth noting that the tensile curve of pre-fatigue specimens deflects twice; the first occurrence correlates with matrix crack reopening, and the second occurs when the uniaxial tensile load exceeds the pre-fatigue stress, and the degree of deflection also gradually decreases or almost disappears.

Automated summary

The tensile-tension fatigue behavior of minicomposite SiC/(PyC/SiC)2/SiC at room temperature was studied, and the residual mechanical properties of specimens were tested after 106 pre-fatigue cycles under different stress levels. It was found that the residual strength initially increases due to stress concentration release and then decreases because of excessive fiber wear. Additionally, the tensile curve of pre-fatigue specimens showed two deflections, with the first correlated with matrix crack reopening and the second occurring when the uniaxial tensile load exceeds the pre-fatigue stress.