OPTIMIZATION OF COATING LAYERS IN THE DESIGN OF CERAMIC FIBER-REINFORCED METAL-MATRIX COMPOSITES

The potential of using coating layers to reduce thermal stresses in th e matrix of composites with a mismatch in coefficients of thermal expa nsion (CTE) of fiber and matrix is investigated. Two thermoelastic sol utions based on a 3-cylinder model are developed and a comprehensive s ensitivity study is conducted. It is shown that the performance of the layer can be defined by the product of its CTE and thickness, and tha t a compensating layer with a sufficiently high CTE can reduce the the rmal stresses in the matrix significantly. A practical procedure offer ing a window of coating layer candidates is proposed. Easy-to-use cont ours of matrix stress reduction factors are produced.