High-temperature deformation behaviour of TiO2-doped 2 mol.% Y2O3-stabilized ZrO2 (8Y-CSZ) under tension and compression


Tekeli S. , Chen T., Nagayama H., Sakuma T., Mecartney M. L.

CERAMICS INTERNATIONAL, vol.33, no.5, pp.869-874, 2007 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 33 Issue: 5
  • Publication Date: 2007
  • Doi Number: 10.1016/j.ceramint.2006.01.014
  • Title of Journal : CERAMICS INTERNATIONAL
  • Page Numbers: pp.869-874

Abstract

The effect of TiO2 addition on the phase stability of 8 mol.% yttria-stabilized cubic zirconia (8Y-CSZ) was investigated. XRD results showed that when the TiO2 amount was less than 5 wt.%, the specimens were entirely single cubic phase; further addition of TiO2 (5 wt.% or more) destabilized cubic zirconia phase and caused the formation of tetragonal phase. The amount of tetragonal phase increased with increasing TiO2 content in the 8Y-CSZ matrix. The high-temperature deformation behavior of TiO2-doped 8Y-CSZ was also studied under both tension and compression. The stress exponent and the activation energy values for 10 wt.% TiO2-doped 8Y-CSZ were found to be 1 and 340 kJ/mol, respectively, using strain rate data from compression tests. The microstructure after and prior deformation was investigated using TEM. The grain shape remained equiaxed after extensive deformation but a high degree of residual stress developed. Under tension the addition of TiO2 vastly decreased the flow stress for 8Y-CSZ and increased elongation to failure. The maximum elongation for 10 wt.% TiO2-doped 8Y-CSZ was 203% at 1400 degrees C and at an initial strain rate of 1.3 x 10(-4) s(-1) with a flow stress of 8 MPa, indicating the superplastic nature of this material. (C) 2006 Elsevier Ltd and Techna Group S.r.1. All rights reserved.