The role of diffusion creep in the superplastic deformation of 3 mol% yttria stabilized tetragonal zirconia

• Published in: Scripta materialia Vol. 42; no. 3; pp. 241 - 248
• Main Author: Chokshi, Atul H
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Ltd 17.01.2000; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; CREEP; DEFORMATION; Deformation and plasticity (including yield, ductility, and superplasticity); Diffusion; ELONGATION; Exact sciences and technology; GRAIN SIZE; Interface-reaction; MATERIALS SCIENCE; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physics; PLASTICITY; Superplasticity; YTTRIUM OXIDES; Zirconia; ZIRCONIUM OXIDES; Zirconia; Interface-reaction; Superplasticity; Creep; Diffusion; Diffusion creep; Superplastic deformation; Mechanical properties; Plastic properties; Stabilized zirconia; Plastic deformation; Experimental study
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/S1359-6462(99)00340-1

The deformation behavior of high purity superplastic 3YTZ is characterized by n=2, p=3 at high stresses, and n=3 and p=1 at low stresses. A recent analysis by Berbon and Langdon, based on a model by Arzt et al., is capable of rationalizing some of the experimental data in terms of diffusion creep from a limited number of discrete sources/sinks. An approach involving rearrangement casued by grain growth can explain the retention of an equiaxed grain size even during diffusion creep. The lack of appropriate diffusion data severely restricts the validity of conclusions based on a good match between experimental data and theoretical predictions. Based on the model by Arzt et al., a critical grain size is developed beyond which conventional Coble diffusion creep will operate. Experiments at coarser grain sizes are necessary to validate the approach based on diffusion creep. A complete analysis for deformation in 3YTZ must account for the influence of impurity content on the transition from napprox2 at high stresses to napprox3 at low stresses.