Preparation and Mechanical Properties of Nanocobalt Coated Al2O3-TiC Composites

2007 ◽  
Vol 334-335 ◽  
pp. 913-916 ◽  
Author(s):  
Yan Sheng Yin ◽  
Shou Gang Chen ◽  
Xue Ting Chang ◽  
Alan Kin Tak Lau
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Fracture Surface ◽  
Bending Strength ◽  
Liquid Phase Sintering ◽  
Sem Images ◽  
Coating Layers ◽  
Cobalt Coating ◽  
Refinement Effect

Al2O3-TiC composites were fabricated by hot-pressing Cobalt coated powders at low temperature through liquid phase sintering. Cobalt coating layers effectively hinder the growth of grain and harmful reaction between Al2O3 and TiC particles, which would improve the mechanical properties of Al2O3-TiC composites. The hardness decreases with the increase of Co content and the bending strength was enhanced to 782MPa owing to the grain refinement effect of Co phase. The fracture toughness, about 9.23 MPa.m1/2, was measured for the composites containing 3wt% Co sintered at 1550°C. SEM images of fracture surface show that the toughening effect should be attributed to the conversion of fracture mode caused by the Co phase.

scholarly journals Sintering Mechanism, Microstructure Evolution, and Mechanical Properties of Ti-Added Mo2FeB2-Based Cermets

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1889
Author(s):  
Yupeng Shen ◽  
Zhifu Huang ◽  
Lei Zhang ◽  
Kemin Li ◽  
Zhen Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Rupture Strength ◽  
Liquid Phase Sintering ◽  
Maximum Hardness ◽  
Liquid Phases ◽  
Ti Content ◽  
Ti Addition

Four series of Mo2FeB2-based cermets with Ti contents between 0 wt.% and 1.5 wt.% in 0.5 wt.% increments were prepared by in situ reaction and liquid phase sintering technology. Influences of Ti on microstructure and mechanical properties of cermets were studied. It was found that Ti addition increases formation temperatures of liquid phases in liquid-phase stage. Ti atoms replace a fraction of Mo atoms in Mo2FeB2 and the solution of Ti atoms causes the Mo2FeB2 crystal to be equiaxed. In addition, the cermets with 1.0 wt.% Ti content exhibit the smallest particle size. The solution of Ti atoms in Mo2FeB2 promotes the transformation of Mo2FeB2 particles from elongated shape to equiaxed shape. With Ti content increasing from 0 wt.% to 1.5 wt.%, the hardness and transverse rupture strength (TRS) first increase and then decrease. The maximum hardness and TRS occur with 1.0 wt.% Ti content. However, the fracture toughness decreases as Ti content increases. The cermets with 1.0 wt.% Ti content show excellent comprehensive mechanical properties, and the hardness, fracture toughness, and TRS are HRA 89.5, 12.9 MPa∙m1/2, and 1612.6 MPa, respectively.

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.

Effect of Rare-Earth Oxides Additive on Liquid Phase Sintered SiC

2014 ◽  
Vol 602-603 ◽  
pp. 407-411 ◽  
Author(s):  
Yu Hong Chen ◽  
Liang Jiang ◽  
Li Li Zhang ◽  
Zhen Kun Huang ◽  
Lan Er Wu
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Liquid Phase ◽  
Bending Strength ◽  
Sintered Sample ◽  
Linear Shrinkage ◽  
Rare Earth Oxides ◽  
Liquid Phase Sintering ◽  
Fine Grained ◽  
Cationic Radius

The densification of α-SiC occurred by liquid-phase sintering mechanism with AlN-RE2O3(RE=Nd, Gd, Y, Lu) was studied. The total additive content was fixed at 15 wt%. Cold isostatically pressed samples were sintered at 1800-1950 °C under N2atmosphere for 1 h. The linear shrinkage and weight loss of the samples were about 17-20% and 2-5%, respectively. The mechanical properties and microstructure of sintered samples were investigated. The experimental results showed that the fracture toughness of samples was 6-8 MPa·m1/2, the hardness was in the range of 18-21 GPa and the bending strength was in the range of 400-500 MPa. It was found that a decrease in the cationic radius of the rare-earth oxides was accompanied by an increase in hardness and flexural strength of the SiC ceramics, whereas the fracture toughness was improved by incorporating rare-earth oxides of larger cationic radius. The morphology (SEM) of sintered sample showed a fine grained microstructure with equiaxed grains. Fracture mode was intergranular fracture.

Button of Hydroxyapatite Composite for Craniotomy Flap Fixation: Fabrication and Mechanical Properties

2020 ◽  
Vol 841 ◽  
pp. 248-253
Author(s):  
Anirut Raksujarit ◽  
Sittiporn Punyanitya
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Liquid Phase Sintering ◽  
Bovine Bone ◽  
Outer Plate ◽  
Maximum Value ◽  
Hydroxyapatite Composite ◽  
Flap Fixation ◽  
Powder Compression

This paper deals with the development of button made from a hydroxyapatite (HA) and bioglass composite. The HA powder derived from the bovine bone were added 2.5 and 5 wt% of P2O5-CaO-Na2O-bases glass and subsequently sintered at 1200 - 1350 °C to form the HA ceramics. It was observed that the densest HA ceramic could be achieved for the sample composed of hydroxyapatite with the addition of 5 wt% of bioglass and sintered at 1300°C, resulting in the maximum value of bending strength of about 77 MPa, which ensured the use in load bearing applications of this HA ceramic. The HA and 5 wt% bioglass composite is designed as a button for reattach the bone flap after a craniotomy procedure. Each device is comprised of an inner plate and an outer plate. The fabrication processing was used the powder compression and then sintering at 1300°C for 3 h. The button have fracture toughness (K1C) values of 1.3±0.1 MPa.m1/2 and bending strength of 65.7±3.8 MPa. The liquid phase sintering of this sample contributed to the high mechanical properties that can be use as craniotomy flap fixation.

The Influence of Processing Parameters on Mechanical Properties of Spark Plasma Sintered Chromium Carbide Based Cermets

2017 ◽  
Vol 267 ◽  
pp. 162-166
Author(s):  
Kristjan Juhani ◽  
Jüri Pirso ◽  
Marek Tarraste ◽  
Mart Viljus ◽  
Sergei Letunovitš
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Chromium Carbide ◽  
Processing Parameters ◽  
Liquid Phase Sintering ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintered Chromium

Present paper discusses the influence of spark plasma sintering (SPS) on the microstructure and perfomances of chromium carbide based cermets. The effect of SPS parameters (temperature, pressure) is discussed. It is shown that SPS enables to produce more fine grained chromium carbide based cermets compared to conventional liquid phase sintering. Hardness and fracture toughness are exhibited.

The Influence of Sintering Temperature on the Mechanical Properties and Microstructure of Carbon Nanotubes/Zirconia/Hydroxyapatite Biocomposites

2013 ◽  
Vol 423-426 ◽  
pp. 38-42
Author(s):  
Ai Min Li ◽  
Kang Ning Sun ◽  
Run Hua Fan
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Fracture Surface ◽  
Bending Strength ◽  
Electronic Materials ◽  
Sintering Temperature ◽  
Testing Machine ◽  
Materials Testing ◽  
Hot Pressing Sintering

Carbon nanotubes/zirconia/hydroxyapatite biocomposites was prepared by hot-pressing sintering under Ar atmosphere. The influence of sintering temperature on the mechanical properties and microstructure of carbon nanotube/zirconia/hydroxyapatite biocomposites was studied. We tested the bending strength and fracture toughness by universal electronic materials testing machine. The component of the composites was tested by XRD. The fracture surface of the composites was observed by SEM. The results indicate that the bending strength and fracture toughness of the composites is lower when the sintering temperature is lower than 1200°C. The difference of bending strength and fracture toughness at 1200°C and 1300°C is little. The number of them has risen markedly than the low temperature which reached to189.2MPa and 1.8MPa·m-1/2 respectively. The composition of the composites is mainly of hydroxyapatite, zirconia, carbon nanotubes, and a small amount of calcium phosphate, which indicated that part of the hydroxyapatite has decomposed. SEM photographs show that the fracture surface of the composites sintered at 1200 °C and 1300 °C is ductile fracture status and has bigger density.

Preparation and Properties of CNTs-Ti3Al/B4C Composites

2011 ◽  
Vol 399-401 ◽  
pp. 377-380
Author(s):  
Yan Hua Fan ◽  
Li Hua Dong ◽  
Bo Yang Liu ◽  
Yan Sheng Yin
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
High Energy ◽  
Hot Press ◽  
Technical Process ◽  
Solid Reaction ◽  
Sem Images ◽  
Energy Ball ◽  
Hot Press Sintering

CNTs-TiAl/B4C composite has been obtained by high energy ball milling and hot press sintering. These technical process promoted the solid reaction and resulted in the formation of composites comprising Ti-Al, TiC, TiB2 and B4C. The SEM images and measurement of the mechanical properties proved that the addition of 1.5wt.% CNTs further improves the fracture toughness and the bending strength of TiAl/B4C composites.

Effect of Glassy Phase Additions to Zirconia on its Mechanical Properties

2012 ◽  
Vol 727-728 ◽  
pp. 940-944
Author(s):  
Vera Lúcia Praxedes de Oliveira ◽  
Marcelo Henrique Prado da Silva ◽  
Eduardo de Sousa Lima ◽  
Claudinei dos Santos ◽  
Luis Henrique Leme Louro
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Mechanical Strength ◽  
Glassy Phase ◽  
Vickers Microhardness ◽  
Liquid Phase Sintering ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Four Point Bending

Glasses with two different compositions were added to yttria-stabilized zirconia TZP powder: a CAS glass and a bioactive glass. These additions allowed liquid phase sintering to occur at temperature as low as 1300 °C. The concentrations of each glass additions were of 1, 3, and 5 wt%. The prepared compositions were uniaxially pressed at 50 MPa and sintered at 1300oC for 2 hours. The sintered samples were characterized for their mechanical properties, by measuring four-point bending mechanical strength, Vickers microhardnesses, and fracture toughness ( KIc ). Vickers microhardness measured values ranged from 10 to 12 GPa, while fracture toughness, from 3.8 to 4.4 MPa.m1/2. The flexural mechanical strength was situated between 302 and 408 MPa. The achieved mechanical properties, from sintered samples were possible due to glassy phase additions. These properties, associated to biocompatibility, enable such materials to be used in different applications, including bioceramics.

Effect of Ti(C0.7N0.3) Content on the Microstructure and Mechanical Properties of Ni Bonded NbC-Ti(C0.7N0.3) Based Cermets

2018 ◽  
Vol 274 ◽  
pp. 43-52
Author(s):  
S.G. Huang ◽  
J. Vleugels ◽  
H. Mohrbacher ◽  
M. Woydt
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Grain Size ◽  
Liquid Phase ◽  
Grain Growth ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Partial Replacement ◽  
Microstructural Investigation

NbC-xTi (C0.7N0.3)-10Ni-7.5VC (vol%) based cermets with 0, 5, 10, 15 or 25 vol% Ti (C0.7N0.3) were prepared by conventional pressureles liquid phase sintering at 1420°C in vacuum. Detailed microstructural investigation was performed by SEM, EPMA and XRD analysis. Sintering results indicated that the partial replacement of NbC by Ti (C0.7N0.3) had a significant effect on the carbide grain growth, microstructure, hardness as well as fracture toughness of the fully densified NbC-based cermets. The Ti (C0.7N0.3)-free NbC cermet was composed of homogeneous cubic (Nb,V)C solid solution grains, whereas core-rim structured NbC grains were observed in cermets with Ti (C0.7N0.3) addition. All sintered cermets with  15 vol% Ti (C0.7N0.3) were composed of a fcc solid solution Ni binder and a cubic core-rim solid solution (Nb,V,Ti)C phase with a Nb-rich core and a Ti-rich rim. 3.8 vol% of residual pristine Ti (C0.7N0.3) was present in the cermets with 25 vol% Ti (C0.7N0.3) addition. The 15 vol% Ti (C0.7N0.3) starting powder based cermet exhibited the finest average NbC grain size of 1.48 μm, with a core-rim structure and an interesting combination of hardness (1486 kg/mm2) and fracture toughness (8.7 MPa.m1/2).

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