Effects of the Content of ZrO2 Nanoparticles on the Microstructure and Properties of Al2O3-TiC-ZrO2 Micro-Nano-Composites

2013 ◽  
Vol 652-654 ◽  
pp. 304-307
Author(s):  
Wei Min Liu ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Microstructural Characterization ◽  
Zro2 Nanoparticles ◽  
Nano Composites ◽  
Sintering Aids ◽  
Agglomeration Effect ◽  
The Matrix

Al2O3-TiC-ZrO2 micro-nano-composites with addition of ZrO2 nanoparticles were fabricated by vaccum hot pressing with Mo and Ni powders as sintering aids. Results showed that the mechanical properties and relative density of the micro-nano-composites increased firstly and then decreased with the increase in the content of ZrO2 nanoparticles. Al2O3-TiC-ZrO2 micro-nano-composites containing about 4vol% ZrO2 nanoparticles have the highest synthetical properties, its flexural strength, Vicker's hardness, Fracture Toughness and relative density are 920MPa, 20.4GPa, 6.3MPa•m1/2 and 98.9%, respectively. The microstructural characterization revealed that adding proper ZrO2 nanoparticles to the matrix can greatly strengthen the grain boundaries, causing more transgranular fractures and consuming more fracture energy. The excessive amount of ZrO2 nanoparticles may bring about agglomeration effect, leading to the decrease of properties of the micro-nano-composites.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

Effects of Sintering Additives on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics by GPS

2010 ◽  
Vol 105-106 ◽  
pp. 27-30 ◽  
Author(s):  
Wei Ru Zhang ◽  
Feng Sun ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Porous Silicon ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Nitride Ceramics

Silicon nitride ceramics were prepared by gas pressure sintering (GPS) with different sintering additives, including La2O3, Sm2O3 and Al2O3. Effect of sintering additives on the phase-transformation, microstructure and mechanical properties of porous silicon nitride ceramics was investigated. The results show that the reaction of sintering additives each other and with SiO2 had key effects on the phase-transformation, grain growing and grain boundaries. With 9MPa N2 atmosphere pressure, holding 1h at 1850°C, adding 10wt% one of the La2O3, Sm2O3, Al2O3, porous silicon nitride was prepared and the relative density was 78%, 72%, 85% respectively. The flexural strength was less than 500MPa, and the fracture toughness was less than 4.8MPam1/2. Dropping compounds sintering additives, such as La2O3+Al2O3, Sm2O3+Al2O3 effectively improves the sintering and mechanical properties. The relative density was 99.2% and 98.7% with 10wt% compounds sintering additives. The grain ratio of length to diameter was up to 1:8. The flexural strength was more than 900MPa, and the fracture toughness was more than 8.9MPam1/2.

Microstructure, Mechanical Properties, Sintering and Fracture Behavior of Ti(C, N) Based Cermets Granules/Ti(C, N) Based Cermets Composite

2020 ◽  
Vol 837 ◽  
pp. 139-145
Author(s):  
Ai Jun Liu ◽  
Gang Li ◽  
Ning Liu ◽  
Ke Bei Chen ◽  
Hai Dong Yang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Fracture Behavior ◽  
Rupture Strength ◽  
Binder Phase ◽  
Hard Phase ◽  
Opposite Trend ◽  
The Matrix ◽  
Sintering Properties

Effect of Ti (C,N) based cermets granule on the microstructure, mechanical properties, sintering and fracture behavior of Ti (C,N) based cermets was investigated. Results show that the Ti (C,N) based cermets granules distribute in the matrix homogeneously. A nanoindentation study was performed on hard phase and binder phase in the matrix and granule. With the increase of granules content, sintering properties is worse. With the increase of granules content, transverse rupture strength (TRS) and relative density decrease gradually, while the hardness has an opposite trend. The fracture toughness increases firstly with increasing granule, and then decreases with the further increase of granules. Higher fracture toughness of the cermets is mainly owing to the crack branch and higher fracture energy of coarse granule.

Microstructures and Mechanical Properties of B4C-TiB2 Composite Prepared by Hot Pressure Sintering

2010 ◽  
Vol 434-435 ◽  
pp. 50-53 ◽  
Author(s):  
Xin Yan Yue ◽  
Shu Mao Zhao ◽  
Liang Yu ◽  
Hong Qiang Ru
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Microstructural Analysis ◽  
Crack Deflection ◽  
Second Phase ◽  
Fine Grain ◽  
Pull Out ◽  
Microstructures And Mechanical Properties

B4C-TiB2 composite was prepared using hot pressure sintering. The microstructures and mechanical properties of the B4C-TiB2 composite were investigated. The B4C-TiB2 composite with 43 mass % TiB2 showed the optimized properties. The relative density, hardness, flexural strength and fracture toughness of that were 98.2 %, 25.9 GPa, 458 MPa and 8.7 MPa•m1/2, respectively. A number of toughening mechanisms, including fine grain, crack deflection and grain pull-out, were observed during microstructural analysis of the composite. The fracture mode of the B4C-TiB2 composite was greatly affected by the existence of the second phase of TiB2.

Effect of Iron Additive on the Sintering Behavior of Hot-Pressed ZrC-W Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1764-1766 ◽  
Author(s):  
Yu Jin Wang ◽  
Lei Chen ◽  
Tai Quan Zhang ◽  
Yu Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Hot Press ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties ◽  
Hot Press Sintering

The ZrC-W composites with iron as sintering additive were fabricated by hot-press sintering. The densification, microstructure and mechanical properties of the composites were investigated. The incorporation of Fe beneficially promotes the densification of ZrC-W composites. The relative density of the composite sintered at 1900°C can attain 95.3%. W2C phase is also found in the ZrC-W composite sintered at 1700°C. The content of W2C decreases with the increase of sintering temperature. However, W2C phase is not identified in the composite sintered at 1900°C. The flexural strength and fracture toughness of the composites are strongly dependent on sintering temperature. The flexural strength and fracture toughness of ZrC-W composite sintered at optimized temperature of 1800°C are 438 MPa and 3.99 MPa·m1/2, respectively.

Large Bulk Al2O3/ZrO2 (Y2O3) Nanocrystalline Composites Prepared by Combustion Synthesis under High Gravity

2010 ◽  
Vol 434-435 ◽  
pp. 9-12 ◽  
Author(s):  
Zhong Min Zhao ◽  
Long Zhang ◽  
Chuan Zeng Pan ◽  
Quan Yang ◽  
Zhen Sheng Qu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Combustion Synthesis ◽  
High Gravity ◽  
Gravity Level ◽  
Nanocrystalline Composites ◽  
Large Bulk ◽  
The Matrix ◽  
High Gravity Field

The large bulk Al2O3/ZrO2 (Y2O3) eutectics were achieved by combustion synthesis in high-gravity field. With increasing high-gravity level, the matrix of eutectics transformed the rod-shaped colonies from the cellular ones, and the nanocrystalline microstructures came into existence as the high-gravity level was larger than 200g. The relative density, hardness, flexural strength and fracture toughness increased simultaneously with increasing high-gravity level, and reached the maximum values of 98.6%, 18.6GPa, 1248MPa and 15.6MPa•m1/2 respectively as the high-gravity level was 250g.

Mechanical Properties of SiC Processed with Nanometer-Sized Powder and Polytitanocarbosilane

2007 ◽  
Vol 352 ◽  
pp. 73-76 ◽  
Author(s):  
Naoki Matsunaga ◽  
Nobuhiro Hidaka ◽  
Soichiro Sameshima ◽  
Yoshihiro Hirata
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Polyacrylic Acid ◽  
Shape Factor ◽  
Weibull Modulus ◽  
Powder System ◽  
Powder Compacts

A bimodal powder system of 800 nm SiC (75 vol%) - 30 nm SiC (25 vol%) was dispersed at 20 vol% solid in a 0.3 M Y(NO3)3 solution containing 0.2 μm Al2O3 and 1.0 mg/m2 polyacrylic acid (PAA: dispersant). The SiC (97.6 vol%)-Al2O3 (1.2 vol%)-Y2O3 (1.2 vol%)-PAA system suspension was consolidated by casting in a gysum mold. Polytitanocarbosilane (PTC) of 3 vol% was infiltrated into the SiC compact calcined at 800 °C to increase the mechanical properties and Weibull modulus. Both the calcined powder compacts with and without PTC were hot-pressed to relative density above 97 % at 1950 °C. The hot-pressed SiC with or without PTC provided the following excellent mechanical properties: average four-point flexural strength of 911 and 812 MPa, fracture toughness of 5.2 and 6.0 MPa·m1/2, and Weibull modulus 11.3 and 5.8 for PTC addition and no addition, respectively. The PTC addition was effective to decrease the shape factor of flaw and increased the strength and Weibull modulus.

Influence of Cr2O3 Addition on the Properties of TiAl Composites

2011 ◽  
Vol 230-232 ◽  
pp. 789-792
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Fang Ni Du
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Synthesis Method ◽  
Strengthening Mechanism ◽  
Reaction Synthesis ◽  
The Matrix ◽  
Method Effects ◽  
Particulate Reinforced

Using Ti, Al and Cr2O3 as starting materials, Al2O3 particulate reinforced TiAl composites have been fabricated by in-situ reaction synthesis method. Effects of the Cr2O3 addition on the microstructures and mechanical properties of the TiAl/Al2O3 composites were investigated in detail. The results show that the composites have a matrix of TiAl, Ti3Al, and minor Cr containing phases, and a second reinforcement Al2O3. The addition of Cr2O3 effectively refined the structure of the matrix, and as a result, the mechanical properties of TiAl composites are improved. At Cr2O3 7.36 wt%, the flexural strength and fracture toughness reach the maximum values of 634.62 MPa and 9.79 MPa·m1/2, which are increased by 80% and 30%, respectively. The strengthening mechanism is also discussed.

scholarly journals Investigating the Mechanical Properties of ZrO2-Impregnated PMMA Nanocomposite for Denture-Based Applications

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1344 ◽  
Author(s):  
Saleh Zidan ◽  
Nikolaos Silikas ◽  
Abdulaziz Alhotan ◽  
Julfikar Haider ◽  
Julian Yates
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Impact Strength ◽  
Flexural Strength ◽  
Flexural Modulus ◽  
Surface Hardness ◽  
Bending Test ◽  
Zro2 Nanoparticles ◽  
Control Group ◽  
The Mean

Acrylic resin PMMA (poly-methyl methacrylate) is used in the manufacture of denture bases but its mechanical properties can be deficient in this role. This study investigated the mechanical properties (flexural strength, fracture toughness, impact strength, and hardness) and fracture behavior of a commercial, high impact (HI), heat-cured denture base acrylic resin impregnated with different concentrations of yttria-stabilized zirconia (ZrO2) nanoparticles. Six groups were prepared having different wt% concentrations of ZrO2 nanoparticles: 0% (control), 1.5%, 3%, 5%, 7%, and 10%, respectively. Flexural strength and flexural modulus were measured using a three-point bending test and surface hardness was evaluated using the Vickers hardness test. Fracture toughness and impact strength were evaluated using a single edge bending test and Charpy impact instrument. The fractured surfaces of impact test specimens were also observed using a scanning electron microscope (SEM). Statistical analyses were conducted on the data obtained from the experiments. The mean flexural strength of ZrO2/PMMA nanocomposites (84 ± 6 MPa) at 3 wt% zirconia was significantly greater than that of the control group (72 ± 9 MPa) (p < 0.05). The mean flexural modulus was also significantly improved with different concentrations of zirconia when compared to the control group, with 5 wt% zirconia demonstrating the largest (23%) improvement. The mean fracture toughness increased in the group containing 5 wt% zirconia compared to the control group, but it was not significant. However, the median impact strength for all groups containing zirconia generally decreased when compared to the control group. Vickers hardness (HV) values significantly increased with an increase in ZrO2 content, with the highest values obtained at 10 wt%, at 0 day (22.9 HV0.05) in dry conditions when compared to the values obtained after immersing the specimens for seven days (18.4 HV0.05) and 45 days (16.3 HV0.05) in distilled water. Incorporation of ZrO2 nanoparticles into high impact PMMA resin significantly improved flexural strength, flexural modulus, fracture toughness and surface hardness, with an optimum concentration of 3–5 wt% zirconia. However, the impact strength of the nanocomposites decreased, apart from the 5 wt% zirconia group.

Densification, Microstructure, and Behavior of Hydroxyapatite Ceramics Sintered by Using Spark Plasma Sintering

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Shufeng Li ◽  
Hiroshi Izui ◽  
Michiharu Okano
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Young’S Modulus ◽  
Spark Plasma Sintering ◽  
Young's Modulus ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Temperature And Pressure

This paper discusses the dependence of the mechanical properties and microstructure of sintered hydroxyapatite (HA) on the sintering temperature and pressure. A set of specimens was prepared from as-received HA powder and sintered by using a spark plasma sintering (SPS) process. The sintering pressures were set at 22.3MPa, 44.6MPa, and 66.9MPa, and sintering was performed in the temperature range from 800°Cto1000°C at each pressure. Mechanisms underlying the interrelated temperature-mechanical and pressure-mechanical properties of dense HA were investigated. The effects of temperature and pressure on the flexural strength, Young’s modulus, fracture toughness, relative density, activation energy, phase stability, and microstructure were assessed. The relative density and grain size increased with an increase in the temperature. The flexural strength and Young’s modulus increased with an increase in the temperature, giving maximum values of 131.5MPa and 75.6GPa, respectively, at a critical temperature of 950°C and 44.6MPa, and the fracture toughness was 1.4MPam1∕2 at 1000°C at 44.6MPa. Increasing the sintering pressure led to acceleration of the densification of HA.

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