Abstract:Residual thermal stresses (RTS) of SCS-6 SiC/Ti-24Al-11Nb composite were analyzed by using finite element method (FEM). Three models of fiber array in the composite and the effect of fiber distance on the RTS were discussed. In all the three models compressive stress was found in the radial direction and tensile stress in the tangential direction. It is pointed out that, in real composite system, hexagonal fiber geometry is superior because the distribution and the
magnitude of the residual stress are similar to those in single fiber model. In square fiber geometry, it is easier to make the matrix crack due to the larger residual tangential stress. RTS becomes very large and changes violently when the fiber distance is less than 15μm or so, therefore too high fiber volume is apt to result in matrix crack.

Key words: titanium matrix composite; SiC fiber; residual thermal stress; finite element method