MICRO-MACRO EXPERIMENTAL STUDY ON STRESS-INDUCED TRANSFORMATION PLASTIC ZONES IN TETRAGONAL ZIRCONIA POLYCRYSTALLINE CERAMICS

1993 ◽  
pp. 571-576
Author(s):  
Q.P. Sun ◽  
Z.J. Zhao ◽  
X.L. Qing ◽  
F.L. Dai ◽  
X.J. Xu
Keyword(s):  
Experimental Study ◽  
Tetragonal Zirconia ◽  
Polycrystalline Ceramics ◽  
Plastic Zones

Experimental Study of Stress-Induced Localized Transformation Plastic Zones in Tetragonal Zirconia Polycrystalline Ceramics

1994 ◽  
Vol 77 (5) ◽  
pp. 1352-1356 ◽  
Author(s):  
Qingping Sun ◽  
Zhijun Zhao ◽  
Weizhe Chen ◽  
Xinglin Qing ◽  
Xiaojian Xu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Tetragonal Zirconia ◽  
Polycrystalline Ceramics ◽  
Plastic Zones

Model analysis of boundary residual stress and its effect on toughness in thin boundary layered yttria-stabilized tetragonal zirconia polycrystalline ceramics

2000 ◽  
Vol 15 (3) ◽  
pp. 727-732 ◽  
Author(s):  
J. L. Shi ◽  
Z. L. Lu ◽  
J. K. Guo
Keyword(s):  
Residual Stress ◽  
Tetragonal Zirconia ◽  
Ceramic Composites ◽  
Boundary Phase ◽  
Thin Boundary Layer ◽  
Maximum Increase ◽  
Proposed Model ◽  
Polycrystalline Ceramics ◽  
Polycrystalline Ceramic ◽  
Continuous Boundary

The average thermal residual stress in a continuous boundary phase in polycrystalline ceramic composites was calculated with a simple thin boundary layer model, and a criterion for the self-cracking of the boundary phase was derived under a certain assumption. From the proposed model, the toughness of the materials can be increased by both tensile and compressive stress at boundaries when the crack propagates transgranularly. The toughness will be increased when the stress at boundary is compressive for intergranular fracture mode. The maximum increase is predicted to be achieved at boundary phase contents below 33%. The experimental results for yttria-stabilized tetragonal zirconia polycrystalline ceramics doped with different kinds of grain-boundary phase is in a qualitative agreement with the prediction by the model, but the toughness increase is largely dependent on the distribution feature of glass phases.

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

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