Shape memory effect in Na0.5Bi0.5TiO3-based ferroelectric ceramics

Shape memory materials (SMMs) are a class of smart materials that generate recoverable residual deformation. Among the family of SMMs, shape memory ceramics (SMC) are more applicable to extreme situations with high temperature, high stress, or corrosive environments. Most of the well-known SMCs are zirconia-based ceramics. Herein, we demonstrate the shape memory behavior of ferroelectric ceramics through a case study on Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT) ceramics. The results show that after heat treatment under stress, there was a large residual strain left in the NBT-BT ceramics. After they were annealed at a temperature above the phase-transition temperature, the residual strain recovered. The maximum recoverable residual strain observed in the NBT ceramic plate was approximately 0.369%. Because most ferroelectric ceramics have a smaller critical stress regarding the stress-induced structural orientation or transformation compared with that of the zirconia-based SMCs, they should be more suitable for SMC applications at a medium stress level. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.