Thermomechanical analysis of 0.94Na1/2Bi1/2TiO3-0.06BaTiO3/ZnO composites using finite element method

Abstract

Object-oriented finite element (OOF2) analysis has been carried out on composites constituting of 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT) matrix phase and ZnO inclusions (4%, 7.5%, 10.78%, and 14% by volume). The effect of ZnO inclusions on the thermomechanical properties of NBT-6BT is investigated and the results are compared with theoretical methods. The thermal stress and strain variation are analyzed under the homogeneous and heterogeneous temperature conditions as a function of volume fraction of the inclusions. The residual stresses localized at the NBT-6BT/ZnO interface are evaluated using the real microstructure of the composite (SEM micrographs), thus providing an actual spatial distribution of stress in the material. In the case of a gradient temperature application, orientation of the grain also varies the stress concentration. Based on the above, the depolarization temperature of the composite can be further improved if the ZnO nano-wire/nano-rods are used instead of ZnO nanoparticle/powder (depending on the orientation of nanowire). Further, the elastic loading conditions mimic the experimental response and as expected, material failure initiates at the pores thus validating the model. © 2020 Elsevier B.V.