EFFECT OF DEBONDING AT THE PHASE INTERFACE ON YOUNGS MODULUS OF SINTERED PSZ STAINLESS STEEL COMPOSITE/

A theoretical estimation has been made on the effect of debonding at t he phase interface on Young's modulus in sintered PSZ/stainless steel composites with an abnormal deterioration of Young's modulus. The pres ent analysis is based on Eshelby's equivalent inclusion method and a d ebonding model. A comparison is made between the theoretically predict ed Young's modulus and experimental data for the composites having thr ee different combinations of original powder size. The theoretical cal culation shows that the Young's modulus decreases with increasing frac tion of debonding. The fraction of debonding can be, in turn, predicte d by comparing the theoretical calculation with the experimental data which have been found to depend on the composition of PSZ and original particle size. The particle size dependence on debonding has been dis cussed using the Weibull distribution, which shows that the coarser di spersoids have more debonded interface. The composition dependence has been explained by the variation of interface's residual stress with c omposition, which is generated by the mismatch of thermal expansion co efficients between the matrix and the dispersed particles, and the res idual stress is compressive at the metal-rich side and tensile at the ceramic-rich side. The tensile stress at the interface enhances the de bonding, however, the compressive stress defend it and improve the You ng's modulus. The dependence of the abnormal deterioration of Young's modulus on the composition and particle size has been well accounted f or.