Microstructure and Fracture Toughness of Yttria-Daped Tetragonal Zirconia Polycrystal/Mullite Composites Prepared by an in Situ Method

1989 ◽  
Vol 72 (12) ◽  
pp. 2369-2372 ◽  
Author(s):  
Kiyoshi Okada ◽  
Nozomu Otsuka ◽  
Richard J. Brook ◽  
A. J. Moulson
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
In Situ Method ◽  
Tetragonal Zirconia Polycrystal

In situ fabrication of PAN nanofibrous composites for enhanced toughness

2020 ◽  
Vol 234 (16) ◽  
pp. 3228-3240
Author(s):  
A Zarehshi ◽  
AA Gharehaghaji ◽  
AA Asgharian Jeddi
Keyword(s):  
Fracture Toughness ◽  
Conventional Method ◽  
Polymeric Fibers ◽  
Elongation At Break ◽  
In Situ Fabrication ◽  
In Situ Method ◽  
Novel Approach ◽  
Polymeric Nanofibers ◽  
Recent Developments

Recent developments in nanocomposites that are reinforced with polymeric fibers have heightened the need for a material in fast-moving parts of machines. The research to date has focused on tensile properties of nanocomposites reinforced with polymeric nanofibers, which were produced by the conventional methods. In this work, nanocomposites were fabricated by a novel approach that comprises epoxy resin, epoxy hardener, and PAN nanofibers in which the nanofibrous layer was placed in resin as spun during the electrospinning. Then, a nanocomposite with the same materials was made using the conventional method of layering. There were enhancements in elongation at break, fracture toughness, and stress at break of nanocomposites fabricated by in situ method in comparison with the nanocomposites fabricated using the conventional method of layering.

Effect of TiN Addition on Microstructure and Mechanical Properties of Zirconia Matrix Ceramic Tool Material

2004 ◽  
Vol 471-472 ◽  
pp. 321-325 ◽  
Author(s):  
Jing Sun ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Sui Lian Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Monoclinic Phase ◽  
Tetragonal Zirconia ◽  
Tool Material ◽  
Strengthening Mechanisms ◽  
Microstructure And Mechanical Properties ◽  
Ceramic Tool Material ◽  
Tetragonal Zirconia Polycrystal

In this paper, 3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) and TiN/3Y-TZP(adding TiN particles to 3Y-TZP) composites were fabricated by hot-pressing technique. Phase composition, microstructure and mechanical properties of the composites were investigated. It is shown that the flexural strength, fracture toughness and Vickers hardness of TiN/3Y-TZP was significantly improved by the addition of TiN particles compared with 3Y-TZP. The flexural strength of ZYT2 (20wt% TiN addition) is 1318 MPa. The fracture toughness of ZYT4 (40wt% TiN addition) is 16.8MPa·m1/2. The toughening and strengthening mechanisms were analyzed. The XRD results show that the additing of TiN can hinder the transformation from tetragonal phase to monoclinic phase of 3Y-TZP during fabrication process.

Laser-Assisted Milling of Zirconia with Systematically Determined Machining Conditions

2017 ◽  
Vol 11 (2) ◽  
pp. 258-269
Author(s):  
Toru Kizaki ◽  
◽  
Yusuke Ito ◽  
Naohiko Sugita ◽  
Mamoru Mitsuishi
Keyword(s):  
Fracture Toughness ◽  
Unique Feature ◽  
Elevated Temperatures ◽  
Thrust Force ◽  
Tetragonal Zirconia ◽  
Systematic Method ◽  
Processing Efficiency ◽  
Diamond Tools ◽  
Dental Restoratives ◽  
Tetragonal Zirconia Polycrystal

Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is a promising material for dental restoratives. Although grinding or polishing with diamond tools is widely used to machine Y-TZP, the processing efficiency and cost of the process are problematic. In this study, we applied laser-assisted machining (LAM) to Y-TZP, in which non-diamond tools were used. Unlike LAM applied to other materials, decrease of the fracture toughness at elevated temperatures which is a unique feature of the Y-TZP was adopted as a key mechanism for machinability enhancement. In addition, a systematic method to determine the LAM conditions was proposed. In this study, we explain the LAM condition-determining method, which is based on numerical simulations of the temperature distribution. Secondly, the determining method was evaluated through a series of LAM experiments to obtain the appropriate LAM conditions. Using the determined conditions, LAM of Y-TZP was demonstrated to be effective; the thrust force was reduced by 51.3% and the tool wear was significantly reduced, while no cracks formed on the Y-TZP.

scholarly journals Determination of Hardness and Fracture Toughness of Y-TZP Manufactured by Digital Light Processing through the Indentation Technique

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ziyu Mei ◽  
Yuqing Lu ◽  
Yuxin Lou ◽  
Ping Yu ◽  
Manlin Sun ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Milling Process ◽  
Control Group ◽  
Digital Light Processing ◽  
Hardness Values ◽  
3D Printing Technique ◽  
True Hardness ◽  
Tetragonal Zirconia Polycrystal

Objective. The purpose of the study was to determine the hardness and fracture toughness of dental yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) manufactured by digital light processing (DLP) technology to study its clinical prospects. Methods. The experimental group was DLP-manufactured zirconia, and the control group was milled zirconia. The hardness was investigated under a range of test loads (0.49 N, 0.98 N, 1.96 N, 4.90 N, 9.81 N, 29.42 N, 49.03 N, 98.07 N, and 196.1 N). Meyer’s law was applied to describe the indentation size effect (ISE). Meanwhile, the PSR model and MPSR model were utilized to generate true hardness values. The cracks were observed to be induced by indentation under loads above 49.03 N, while the cracks showed the radial-median type under the load of 196.1 N, under which the fracture toughness was calculated. Results. The true hardness of DLP-manufactured zirconia was 1189 HV based on the PSR model and 1193 HV based on the MPSR model, a bit lower than that of milled zirconia. The fracture toughness was 3.43 ± 0.29   MPa √ m , which showed no statistical difference with the milled zirconia. Conclusion. The dental zirconia manufactured by the DLP 3D printing technique is similar to that manufactured by the conventional milling process in hardness and fracture toughness, thus having a promising future of clinical use.

Microscopic Mechanisms behind the Toughening Behavior of Ceria Stabilized Tetragonal Zirconia/Alumina Nanocomposite for Biomedical Applications

2007 ◽  
Vol 361-363 ◽  
pp. 813-816 ◽  
Author(s):  
Masahiro Nawa ◽  
Kiyotaka Yamada ◽  
Giuseppe Pezzotti
Keyword(s):  
Fracture Toughness ◽  
Biomedical Applications ◽  
Mechanical Performance ◽  
Human Life ◽  
Tetragonal Zirconia ◽  
Confocal Raman Spectroscopy ◽  
Reliability Characteristics ◽  
Monolithic Zirconia ◽  
Confocal Raman

With elongation of average human life, problem such as bone embrittlement and osteoporosis call for quick solution and the expectation for artificial biomaterials heightens. Many ceramics widely used as artificial biomaterials are limited by their poor reliability characteristics. A CeO2 stabilized tetragonal zirconia polycrystalline (Ce-TZP) matrix incorporating nanometer sized Al2O3 particles within the zirconia grains (Ce-TZP/Al2O3) was recently developed. This material experienced significant improvements in both fracture toughness and strength above the standard mechanical performance of monolithic zirconia. In this paper, we performed a macro/microscopic fracture mechanics assessment of this developed Ce-TZP/Al2O3 nanocomposite, in comparison with a 3 mol% Y-TZP according to advanced in situ confocal Raman spectroscopy techniques.

Sinterability of Alumina-Dispersed 3Y-TZP

2006 ◽  
Vol 317-318 ◽  
pp. 37-40
Author(s):  
Bum Rae Cho ◽  
Dong Guk Yeoum
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Micro Hardness ◽  
Drying Method ◽  
Hardness Tester ◽  
Pinning Effect ◽  
High Relative Density ◽  
Al2o3 Particles ◽  
Vickers Micro Hardness ◽  
Tetragonal Zirconia Polycrystal

The effect of Al2O3 addition on sinterability of Tetragonal Zirconia Polycrystal powders including 3mol% Y2O3 (3Y-TZP) was investigated. Each 3Y-TZP powder dispersed with 0.3, 0.6, 0.9 and 1.2wt.% of Al2O3 was prepared by the spray-drying method. The prepared powders were pressed into a disk type and sintered at 1350, 1400, 1450 and 1500 for 2 hours in the air. Resultant microstructures and mechanical properties of specimens were investigated by using Vickers/Micro hardness Tester, FE-SEM and XRD. Most of the specimens showed high relative density over 99% and a higher fracture toughness than pure 3Y-TZP. Al2O3 particles dispersed in 3Y-TZP microstructure depressed grain growth of 3Y-TZP by the pinning effect. Increase in fracture toughness of 3Y-TZP was explained by the crack deflection due to dispersed Al2O3 particles.

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