Role of Grain-Boundary Glass Phase on the Superplastic Deformation of Tetragonal Zirconia Polycrystal

1990 ◽  
Vol 73 (10) ◽  
pp. 3069-3073 ◽  
Author(s):  
Yu-ichi Yoshizawa ◽  
Taketo Sakuma
Keyword(s):  
Grain Boundary ◽  
Superplastic Deformation ◽  
Glass Phase ◽  
Tetragonal Zirconia ◽  
Tetragonal Zirconia Polycrystal

A Re-Appraisal of Cavity Growth Processes in Superplasticity

1990 ◽  
Vol 196 ◽  
Author(s):  
Yan Ma ◽  
Terence G. Langdon
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Superplastic Deformation ◽  
Cavity Growth ◽  
Normal Model ◽  
Experimental Conditions ◽  
Diffusion Growth ◽  
New Model

ABSTRACTIt is well known that cavities are nucleated and grow during the superplastic deformation of many materials. The various theories for cavity growth are examined with special emphasis on the role of growth by diffusion. It is demonstrated that the normal model for the diffusion growth of cavities is inadequate for superplastic materials when the grain boundary lengths are very small. By developing a new model for the growth of an isolated cavity to sizes exceeding the grain size, it is shown that the diffusion process may play a major role in cavity growth under a range of experimental conditions.

Precise Calibration of Displacement Vector Map during Superplastic Deformation in Tetragonal Zirconia Polycrystal

2012 ◽  
Vol 735 ◽  
pp. 101-108
Author(s):  
Kouichi Yasuda ◽  
Taku Okamoto
Keyword(s):  
Measurement Error ◽  
Domain Structure ◽  
Superplastic Deformation ◽  
Displacement Vector ◽  
Tetragonal Zirconia ◽  
Vector Map ◽  
Tetragonal Zirconia Polycrystal

In previous papers, the present authors observed grain motion in tetragonal zirconia polycrystal during superplastic deformation, and showed the displacement vector map of 748 grains. The map had an interesting feature such as transient domain structure. However, the authors did not pay much attention to the measurement error at that time. In this paper, the influence of measurement error on the map was quantitatively investigated. After precise calibration, it was revealed that measurement error did not have much influence on the feature, and statistics of grain motion was discussed on the calibrated map.

Grain-Boundary Structure and Phase-Transformation Mechanism in Yttria-Stabilized Tetragonal Zirconia Polycrystal

2007 ◽  
Vol 558-559 ◽  
pp. 921-926
Author(s):  
Koji Matsui ◽  
Hidehiro Yoshida ◽  
Yuichi Ikuhara
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Grain Boundary ◽  
Grain Growth ◽  
Tetragonal Zirconia ◽  
Cubic Phase ◽  
Phase Boundaries ◽  
Transmission Electron ◽  
Tetragonal Zirconia Polycrystal

The microstructures in 3 mol% Y2O3-stabilized tetragonal zirconia polycrystal (Y-TZP) sintered at 1100°-1650°C were investigated to clarify cubic-formation and grain-growth mechanisms. The cubic phase in Y-TZP appeared at 1300°C and its mass fraction increased with increasing sintering temperature. High-resolution transmission electron microscopy (HRTEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS) measurements revealed that no amorphous layer existed along the grain-boundary faces in Y-TZP, and Y3+ ions segregated not only along the tetragonal-tetragonal phase boundaries but also along tetragonal-cubic phase boundaries. Scanning transmission electron microscopy (STEM) and nanoprobe EDS measurements revealed that the Y3+ ion distribution was nearly homogeneous up to 1300°C, but cubic phase regions with high Y3+ ion concentration clearly formed inside grains at 1500°C. These results indicate that cubic phase regions are formed from the grain boundaries and/or the multiple junctions in which Y3+ ions segregated. We termed such a new diffusive transformation phenomenon “grain boundary segregation-induced phase transformation (GBSIPT)”. The grain-growth mechanism is controlled by the solute-drag effect of Y3+ ions segregating along the grain boundary.

Deformation-induced surface corrugation of superplastic ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 1879-1882 ◽  
Author(s):  
Hiroyuki Muto ◽  
Takatoshi Futami ◽  
Motosugu Sakai
Keyword(s):  
Superplastic Deformation ◽  
Glassy Phase ◽  
Tetragonal Zirconia ◽  
Secondary Phase ◽  
Grain Boundary Sliding ◽  
Specimen Size ◽  
Surface Corrugation ◽  
New Finding ◽  
Boundary Sliding ◽  
Tetragonal Zirconia Polycrystal

A new finding is reported for the surface corrugation induced in the superplastic deformation and flow of 3 mol% yttria-partially stabilized tetragonal zirconia polycrystal and β-spodumene glass ceramic, the former including no secondary phase and the latter having a plenty of glassy phase at grain boundaries. A significant test specimen size effect on the resistance to superplastic deformation is also addressed. These findings are related to the microscopic processes and mechanisms of cooperative grain-boundary sliding.

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