A modified Rietveld method to model highly anisotropic ceramics

Tutuncu G., Motahari M., DAYMOND M. R., Ustundag E.

ACTA MATERIALIA, vol.60, no.4, pp.1494-1502, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 60 Issue: 4
  • Publication Date: 2012
  • Doi Number: 10.1016/j.actamat.2011.11.050
  • Journal Name: ACTA MATERIALIA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1494-1502
  • Istanbul Technical University Affiliated: No

Abstract

High energy X-ray diffraction was employed to probe the complex constitutive behavior of a polycrystalline ferroelectric material in various sample orientations. Pb(Zn,Nb)O-3-Pb(Zr,Ti)O-3 (PZN-PZT) ceramics were subjected to a cyclic bipolar electric field while diffraction patterns were taken. Using transmission geometry and a two-dimensional detector, lattice strain and texture evolution (domain switching) were measured in multiple sample directions simultaneously. In addition, texture analysis suggests that non-180 degrees domain switching is coupled with lattice strain evolution during uniaxial electrical loading. As a result of this material's high strain anisotropy, the full-pattern Rietveld method was inadequate to analyze the diffraction data. Instead, a modified Rietveld method, which includes an elastic anisotropy term, yielded significant improvements in the data analysis results. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.