Using the methods which are applied for estimating strength and toughness of composites reduces trial-and-error rate in their design. One of the mechanisms for strengthening and increasing toughness of composites is through debonding mechanism. Interface strength of reinforcement with matrix and effective surface of debonding greatly affect toughness and strength of these types of materials. In this study, a model was proposed to estimate the effect of interface and matrix strength of composites in increasing tensile toughness and strength. Then, interface strength and its effect in increasing tensile toughness and strength were calculated in a case study of composites containing particle reinforcement in matrix of deep cryogenic treated steel .
