Giant anelastic responses in (BaZrO3-ZnO)-BaTiO3 composite materials
Department of Engineering Physics, University of Wisconsin - Madison, WI 53706-1687, USA
2 Materials Science Program, University of Wisconsin - Madison, WI 53706-1687, US A
3 Department of Engineering Physics, Engineering Mechanics Program, Materials Science Program, University of Wisconsin - Madison, WI 53706-1687, USA
Accepted: 27 February 2011
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.
PACS: 62.40.+i – Anelasticity, internal friction, stress relaxation, and mechanical resonances / 81.05.Mh – Cermets, ceramic and refractory composites
© EPLA, 2011