Experimental study of residual stress distribution in interfacial micro-region of SiCf/Ti17 composites via micro-slotting method

Abstract

Residual stresses in the interface layer significantly affects the mechanical properties of SiCf/Ti17 composites, which inevitably occurs due to the difference in the thermal expansion coefficient during the fabrication process. Therefore, the micro-residual stress at interface layer of SiCf/Ti17 composites should be quantitatively characterized. In this study, the micro-residual stresses at the interface of the composite are released and mapped via micro-slotting method and subset geometric phase analysis (S-GPA). Based on the material microstructure, a residual stress measurement scheme is designed for the interface layer in the radial and tangential directions. And the deformation field, which is calculated via S-GPA, is released, while the corresponding deformation field is obtained via finite element analysis, so that the residual stress can be fitted by above two deformation fields. The results indicate that, in the cross-setion of the fiber, the residual stresses at carbon interface are tensile, which may be beneficial to improve the mechanical properties of the materials. Meanwhile, tensile residual stresses, instead of compressive stresses in the interface layer, do not inhibit energy dissipation during the fracture of the composite.