Residual thermal stresses in metallic and intermetallic matrix composites after cooling from processing temperature

Thermal stresses induced during cooling from the fabrication to ambient temperatures of SCS-6/Ti-6Al-4V and SCS-6/Ti-24Al-4Nb composites are analyzed applying the finite element method. The matrix is modeled as a bilinear elasto-plastic material with work and kinematic hardening. Thermo-mechanical properties of both the fiber and the matrix are temperature dependent. Effects of the free surface of the composite are included in the analysis. It is shown that during cooling the matrix behavior may switch from elastic to elastoplastic and back to elastic. In particular, for the Ti-6Al-4V matrix, the stresses remain below the yield limit and the cooling process is elastic at the beginning (at high temperature) and also when approaching room temperature.