RESIDUAL THERMAL-STRESSES IN A FILAMENTARY SIC/AL COMPOSITE

Residual stresses in a silicon carbide/aluminum (SiC/Al) composite introduced by the cooling process were investigated. The large mismatch of the coefficients of thermal expansion (CTE) between the silicon carbide (SCS-2) fiber and 6061 aluminum matrix tends to produce high residual stresses so that plastic flow of the matrix is inevitable during cool down. The elastoplastic behavior of the composite material was studied. The analysis is based on the successive approximation scheme with the Prandtl-Reuss plastic flow model and von Mises criterion. The three-dimensional state of residual stress in the fiber and matrix was computed. It was found that plastic flow of the matrix relieves the residual stresses in both fiber and matrix. In addition, the longitudinal stress-strain curve at room temperature under uniaxial tension and the thermal strain-temperature relationship of the composite were predicted and compared with experimental results.