Abstract
Composite materials containing particulate BaTiO3 inclusion have been fabricated with BaZrO3-ZnO as the matrix. Giant anelastic responses (abrupt increase in modulus and damping vs. temperature) have been observed after 75 °C aging 24 h in these composites in the temperature region far below the Curie point of BaTiO3. Anomalies disappeared after 185 °C aging 4 h. Such responses are attributed to the constraining negative-stiffness effect of the inclusion. An oxygen vacancy mechanism has been discussed which is considered to be responsible for the negative-stiffness effect. The present work is novel in terms of the idea of manipulation of negative stiffness in ferroelastic inclusions to achieve the desired composite properties.
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