Effect of Short Time Sintering on the Mechanical Properties of Undoped Zirconia Ceramics

2014 ◽  
Vol 629 ◽  
pp. 420-425 ◽  
Author(s):  
Sivanesan Sivakumar ◽  
Ramesh Singh ◽  
Hsien Loong Teow ◽  
Yong Leng Chuan ◽  
Jeffrey Kong Chin Leong
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tetragonal Zirconia ◽  
Matrix Stiffness ◽  
Zirconia Ceramics ◽  
High Relative Density ◽  
The Matrix ◽  
The Many ◽  
Short Time ◽  
Critical Grain Size

Sintering parameters are undoubtedly among the many factors that influence the mechanical properties and hydrothermal ageing resistance of tetragonal zirconia ceramics. In this research, the effect of using short holding times i.e. (1 min., 30 min. and 1 hour) as compared to the conventional 2 hours during sintering of 3 mol% Yttria Tetragonal Zirconia Polycrystals (3Y-TZP) on the mechanical properties were systematically investigated. The research revealed that holding time of 1 minute and sintered at 1400oC yielded a high relative density (above 95% of theoretical density) and high Young’s modulus (above 180 GPa) without compromising on tetragonal phase stability and mechanical properties. The study also revealed that the bulk density is an important parameter governing the matrix stiffness of 3Y-TZPs and that grain size strongly influences the transformability and consequently, the toughness of 3Y-TZPs. The toughness of the ceramic was observed to increase steeply when grains exceeded 0.52 µm, which has been identified as the critical grain size for toughening.

Influence of Manganese Oxide on the Sintering Properties of Ceria-Stabilized Tetragonal Zirconia

2021 ◽  
Vol 1030 ◽  
pp. 179-185
Author(s):  
Ananthan Soosai ◽  
Suresh Muniandy ◽  
Teow Hsien Loong
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Manganese Oxide ◽  
Biomedical Applications ◽  
Tetragonal Zirconia ◽  
Young Modulus ◽  
Pressureless Sintering ◽  
Stabilized Zirconia ◽  
Sintering Properties ◽  
Critical Grain Size

Ceria stabilized zirconia with critical grain size is found to exhibit higher strength and higher resistance towards low temperature moisture degradation, The mechanical properties are greatly influenced by the size of the tetragonal grains. The effectiveness of doping with MnO2 (0.2 to wt %) in retarding degradation mechanical properties of ceria stabilized tetragonal zirconia (Ce-ZrO2) was evaluated by pressureless sintering within a temperature range from 1250°C-1550°C. Impact of manganese oxide to the mechanical properties and ageing resistance to the Ce-ZrO2 is truly beneficial. 0.4 wt% MnO2 at 1450°C revealed that, the tetragonal grain size was not affected by dopant level.With optimum dopant the 3 mol% ceria (3Ce-ZrO2) ceramic demonstarted the Vicker hardness of 11.8 GPa , fracture toughnessof 10.0 MPam1/2, flexural strength 920 MPa and Young modulus of 210 GPa. The 3Ce-ZrO2 doped with 0.4wt% MnO2 sintered 1450°C could be the best building block for biomedical applications.

Microstructure and Mechanical Performance of AZ31-1.7 Wt.% Si Alloy Processed by Cyclic Channel Die Compression

2010 ◽  
Vol 667-669 ◽  
pp. 457-461
Author(s):  
Wei Guo ◽  
Qu Dong Wang ◽  
Man Ping Liu ◽  
Tao Peng ◽  
Xin Tao Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Mechanical Performance ◽  
Chinese Script ◽  
Cast State ◽  
Microstructure And Mechanical Properties ◽  
Mean Grain Size ◽  
The Matrix ◽  
The Mean

Cyclic channel die compression (CCDC) of AZ31-1.7 wt.% Si alloy was performed up to 5 passes at 623 K in order to investigate the microstructure and mechanical properties of compressed alloys. The results show that multi-pass CCDC is very effective to refine the matrix grain and Mg2Si phases. After the alloy is processed for 5 passes, the mean grain size decreases from 300 μm of as-cast to 8 μm. Both dendritic and Chinese script type Mg2Si phases break into small polygonal pieces and distribute uniformly in the matrix. The tensile strength increases prominently from 118 MPa to 216 MPa, whereas the hardness of alloy deformed 5 passes only increase by 8.4% compared with as-cast state.

scholarly journals Morphology and Mechanical Properties of 3Y-TZP Nanofiber Mats

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2097
Author(s):  
Alexander I. Tyurin ◽  
Vyacheslav V. Rodaev ◽  
Svetlana S. Razlivalova ◽  
Viktor V. Korenkov ◽  
Andrey O. Zhigachev ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Phase Composition ◽  
Calcination Temperature ◽  
Tetragonal Zirconia ◽  
Calcination Temperatures ◽  
Nanoindentation Testing ◽  
Average Grain Size ◽  
Nanofiber Mats ◽  
Morphology And Mechanical Properties

The mats of yttria-stabilized tetragonal zirconia nanofibers were prepared using electrospinning. The effect of calcination temperature in the range of 600–1200 °C on their microstructure, phase composition and mechanical properties was investigated. Phase composition of the nanofibers did not change in all ranges of the calcination temperatures, while the average grain size increased from 8 to 39 nm. Nanoindentation testing of the mats showed a decrease in the hysteresis loop energy in samples with higher calcination temperature. Hardness and the elastic modulus measured with the indentation technique were the highest for the mats calcined at 900 °C.

The effect of reduction on the mechanical properties of CeO2 doped tetragonal zirconia ceramics

2004 ◽  
Vol 52 (6) ◽  
pp. 1675-1682 ◽  
Author(s):  
M. Matsuzawa ◽  
M. Abe ◽  
S. Horibe ◽  
J. Sakai
Keyword(s):  
Mechanical Properties ◽  
Tetragonal Zirconia ◽  
Zirconia Ceramics

Mechanical properties and low-temperature aging of tetragonal zirconia polycrystals processed by hot isostatic pressing

2003 ◽  
Vol 18 (10) ◽  
pp. 2415-2426 ◽  
Author(s):  
J. Muñoz-Saldaña ◽  
H. Balmori-Ramírez ◽  
D. Jaramillo-Vigueras ◽  
T. Iga ◽  
G. A. Schneider
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Low Temperature ◽  
Hot Isostatic Pressing ◽  
Tetragonal Zirconia ◽  
Hot Water ◽  
Full Density ◽  
Isostatic Pressing ◽  
Low Temperature Aging ◽  
Temperature Aging

The influence of grain size and density of yttria-tetragonal zirconia polycrystals (Y-TZPs) ceramics on mechanical properties and on low-temperature aging degradation (LTD) in air and in hot water was investigated. A TZP powder containing 3 mol% Y2O3 was consolidated by slip casting and densified by the sintering/hot isostatic pressing (HIP) method. Only the presintered samples that contained less than 0.15% open porosity reached near full density after HIP. The best conditions to reach full density were found to be attained by presintering and HIP both at 1400 °C. At these conditions, some of the best mechanical properties such as modulus of rupture and Weibull modulus reached 1397 ± 153 MPa and, 10.6, respectively. These values were clearly higher than those obtained from sintered bodies and samples hot isostatically pressed at 1600 °C. Aging degradation of 3Y-TZP materials can be avoided through microstructural design. Fully dense materials with a critical grain size <0.36 μm did not show any evidence of degradation after extreme aging conditions at pressurized autoclaving in hot water at 100, 200, and 260 °C for 8 h. We propose a criterion to predict degradation in air as well as in hot water for the characterized materials based on the microstructure and density control of the samples.

scholarly journals Quantitative analysis of microstructure and mechanical properties of Nb–V microalloyed high-strength seismic reinforcement with different Nb additions

2021 ◽  
Vol 40 (1) ◽  
pp. 300-309
Author(s):  
Sheng Huang ◽  
Changrong Li ◽  
Zhiying Li ◽  
Zeyun Zeng ◽  
Yongqiang Zhai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Dislocation Line ◽  
High Strength ◽  
Second Phase ◽  
Seismic Zone ◽  
Niobium Content ◽  
Precipitated Phase ◽  
Microstructure And Mechanical Properties ◽  
The Matrix

Abstract HRB500E seismic steel bars are mainly used in high-rise buildings near the seismic zone. The influence of different niobium contents (0–0.023%) on the microstructure and mechanical properties of HRB500E seismic reinforcement was studied. Results showed that the grain size of ferrite was between 3.6 and 8.3 μm when only V was added. Meanwhile, as the niobium content increases, the ferrite particles are further refined. After adding niobium, the grain contribution increased by 9%. The addition of niobium significantly refined the grain size of HRB500E seismic reinforcement. The second-phase nano-elliptic precipitate is NbC. The precipitated phase is dispersed on the grain boundary and the matrix, and the dislocation density on the matrix promotes the precipitation of NbC particles along the dislocation line. The second-phase precipitation of niobium can form an effective pinning effect and then refine the pearlite spacing. The microhardness and the tensile strength also significantly improved. The yield strength increased from 509 to 570 MPa.

Mechanical Properties and Microstructure of PMMA-ZrO2 Nanocomposites for Dental CAD/CAM

2013 ◽  
Vol 785-786 ◽  
pp. 533-536 ◽  
Author(s):  
Shi Bao Li ◽  
Yi Min Zhao ◽  
Jian Feng Zhang ◽  
Cheng Xie ◽  
Dong Mei Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
In Situ Polymerization ◽  
Zirconia Ceramics ◽  
Sem Images ◽  
The Matrix ◽  
Cad Cam ◽  
Organic Resin

A novel PMMA-ZrO2 composite (PZC) was prepared by resin infiltrated to ceramic method. The composite mechanical properties were evaluated and correlated to its microstructure. Partially sintered zirconia ceramics (PSZC) were made by isostatic pressing and partially sintering. Subsequently, the PZC was prepared by vacuum infiltrating prepolymerized MMA into PSZC, followed by in-situ polymerization. When PSZC-70% was used as the matrix, the bending strength, elastic modulus, and fracture toughness of the prepared composite i.e PZC-70% were 202.56±12.09 MPa, 58.71±3.98 GPa, and 4.60±0.26 MPa·m1/2, corresponding to 25.69%, 23.31%, and 169.01% improvement, respectively, in comparison with the control matrix. Among them, the fracture toughness improvement was the most prominent. According to SEM images of the fracture surfaces, each pore of zirconia skeleton was filled by organic resin contributing to the bending strength improvement. These weak interfaces between zirconia skeleton and organic resin absorbed energy and terminated the growth of microcracks which might be responsible for significant improvement in fracture toughness. This PZC material is anticipated to be a new member of the dental CAD/CAM family.

Thermal Cycling Effect on Mechanical Properties, Grain Size and Residual Stress in Alumina and Yttria-Stabilized Tetragonal Zirconia

2014 ◽  
Vol 875-877 ◽  
pp. 1642-1646
Author(s):  
Jing Zhang
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Thermal Cycling ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Tetragonal Zirconia ◽  
Thermal Cycles ◽  
Optical Applications ◽  
Increasing Temperature

Alumina and zirconia are important materials for energy and optical applications. In this study, the effect of thermal cycling on grain size and residual stress was reported. Residual stress was measured using X-ray diffraction (XRD) sin2ψ method for the as-received and the samples after thermal cycling up to 900 cycles. For alumina, the measured residual stress is approximately 96 MPa in tensile for the as-received material, and increases to its highest value of 480 MPa after 650 thermal cycles. The residual stress decreases from 480 MPa to 96 MPa in tensile with increased thermal cycling from 650 to 900 cycles. The crystallized grain size calculated from the diffraction pattern shows that the mean crystallized grain size is about 93 nm for the as-received and increases to 232 nm after 650 thermal cycles. This result is consistent with the enlarged grain size observed by scanning electron microscopy for the alumina after 650 thermal cycles reported earlier. With continued thermal cycling up to 900 cycles, the crystallized grain size is greatly reduced to 104 nm. It suggests that evolution of the crystallized grain size is correlated with the residual stress. For yttria-stabilized tetragonal zirconia (Y-TZP), the mechanical properties at room temperature, are consistent with the property values provided by the manufacturer. The Young’s modulus of shows a non-linear inverse relationship with increasing temperature. The degradation of the Young’s modulus mostly occurs prior to 400 °C and to a less extent in the temperature range of 400 °C up to 850 °C. The Vickers hardness number for the as-received Y-TZP material decreases to a very small extent after 560 thermal cycles and increases approximately 2%, after 1200 thermal cycles. This is consistent with the trend of the Young’s modulus for thermal-cycled specimens.

Effects of Repeated Plastic Working (RPW) Process on the Structure and Properties of Mg2Si/Mg-Zn-Er Composite

2010 ◽  
Vol 146-147 ◽  
pp. 1222-1226
Author(s):  
Shu Bo Li ◽  
Ya Ling Qin ◽  
Han Li ◽  
Wen Bo Du
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Ultimate Strength ◽  
Matrix Alloy ◽  
Structure And Properties ◽  
Plastic Working ◽  
Magnesium Matrix ◽  
The Matrix ◽  
Silicon Particles

The Mg matrix composite (Mg2Si/Mg-5Zn-2.5Er) was prepared using repeated plastic working (RPW) technique. and the effects of the number of RPW cycles on the microstructure and mechanical properties of these composites were investigated. The results indicated that the added silicon particles fully reacted with the magnesium matrix, and theMg2Si/Mg-5Zn-2.5Er composites were successfully achieved. When the number of RPW cycle increased, the size of the Mg2Si particles decreased, and the grain size of the matrix alloy reached the minimum when 200 RPW cycles was used. The best mechanical properties were also identified as 394 MPa ultimate strength, and 363 MPa yield strength, when 200 RPW cycles were used.

Microstructure and Mechanical Properties of Extruded Mg-Zn-Nd-Y-Zr-Ca Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 385-388
Author(s):  
Qiang Li ◽  
Qu Dong Wang ◽  
Xiao Qing Zeng ◽  
Wen Jiang Ding ◽  
Quanbo Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Cast Alloy ◽  
Casting Process ◽  
Elevated Temperature Strength ◽  
The Matrix ◽  
Zr Alloys

Nd, Y and Ca containing Mg-Zn-Zr alloys are produced by electromagnetic direct-chilling casting process, and extruded at a temperature of 643K with two extrusion ratios of 38:1 and 22:1, respectively. The grain size is markedly reduced from 80µm in as-cast alloy to 2~5µm in as-extruded alloy due to dynamic recrystallization, and lamellar eutectics at grain boundaries in as-cast alloy are broken up and fine precipitates in the matrix come forth during hot extrusions. Mechanical properties of the alloys are measured by tensile test from room temperature to 523K. Nd, Y and Ca are favorable to the strength of the hot-extruded alloy, especially the elevated-temperature strength, which is above 200MPa in ultimate tensile strength at 523K.

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