Mechanical versus electromechanical hardening in relaxor ferroelectric Na1/2Bi1/2TiO3-BaTiO3 with ZnO inclusions

摘要

The stress-strain response of composites constituting relaxor 0.94Na(1/2)Bi(1/2)TiO(3)-0.06BaTiO(3) matrix phase with ZnO inclusions is investigated. The ZnO inclusions are found to increase the transformation stress (unpoled) for the relaxor-ferroelectric transformation and the coercive stress (poled) for domain switching. The plastic and remanent strain decreases with increasing volume fraction of the hard ZnO inclusions. This mechanical hardening mechanism is contrasted quantitatively to electromechanical hardening by comparing the transformation stress and coercive stress to the poling field and coercive field respectively, as well as the corresponding plastic strain from mechanical loading to the total strain quantified by electric field loading. (C) 2019 Published by Elsevier Ltd on behalf of Acta Materialia Inc.