Abstract: A preliminary model for the analysis of thermo-mechanical behaviour of interfacial coatings on the fibers in unidirectional composites have been developed on the solution of thermo-elastic mechan- ics. Thermal stress would be introduced into the composite during cooling because of the mismatch of thermo-mechanical properties among their components. The low modulus coating can effectively reduce the interracial stress caused by different thermal expansion coefficient between fibers and ma- trix, no matter how high or low the expansion coefficients of coatings are in CF/Al and SiC/Ti composite systems, however, high modulus coating can decrease the interfacial compressive stress, only when the thermal expansion coefficient of coating is lower.

Key words: composite, thermal stress, interfacial coating