Cohesive zone modelling of interfacial delamination in PZT thin films

Previous experimental tests have demonstrated that the multilayered Cr/PZT/PLT/Pt/Ti thin films deposited on single crystal Si substrate tend to delaminate along the interface between PZT and Cr layers in a brittle manner.This study starts from modeling based on cohesive zone concept and carries out finite element simulations to check the delamination behavior along the Cr/PZT interface.Two cohesive zone models(CZMs) of exponential type and bilinear type are adopted,and the characteristic CZM parameters are extracted through calibration via the experimental results.The simulation results show that cohesive strength and cohesive energy are the dominating CZM parameters;the bilinear CZM more suitably describes this brittle interfacial delamination;in comparison with typical several mm-thick film/coating materials,the fracture energy of this weak Cr/PZT interface is quite low.Our study demonstrates the applicability of CZM for characterizing the interface fracture behavior of film materials of micrometer thicknesses.