Modified clamped beam bend method for determination of interfacial fracture energy of thermally sprayed Yttria Stabilised Zirconia over steel

A novel modified clamped beam bend method is developed to measure interface fracture energy of metal/ceramic interfaces. Finite element simulations are used to determine the energy release rate as a function of crack length and loading offset. The experimental procedure for the geometry is demonstrated by measuring interface fracture energy of thermally sprayed Yttria Stabilised Zirconia (YSZ) coating on steel. A smaller load offset is used to create the pre-crack. Subsequently, a larger offset is used to propagate the interface pre-crack, with the signature in the load-displacement curve used to determine the corresponding critical load. Interface fracture energy is obtained as critical energy release rate, G_C, using numerically computed values of J–integral. Finite element simulations are further performed for various coating to substrate thickness ratios and modulus ratios, to characterize trends in energy release rate and phase angles and assess the applicability of the geometry across other material systems.