Preparation and Characterization of Alumina based TiNn and SiCn Composites

2002 ◽  
Vol 740 ◽  
Author(s):  
Mats Carlsson ◽  
Mats Johnsson ◽  
Annika Pohl
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Ceramic Composites ◽  
Processing Route ◽  
Nano Structure ◽  
Plasma Sintering ◽  
Water Based ◽  
Spark Plasma

ABSTRACTCeramic composites containing 2 and 5vol. % of nanosized commercially available TiN and SiC particles in alumina were prepared via a water based slurry processing route followed by spark plasma sintering (SPS) at 75 MPa in the temperature range 1200–1600°C. Some of the samples could be fully densified by use of SPS already after five minutes at 1200°C and 75 MPa. The aim was to control the alumina grain growth and thus obtain different nano-structure types. The microstructures have been correlated to some mechanical properties; e.g. hardness and fracture toughness.

Thermal Stability and Mechanical Properties of Nanocrystalline L12 Al3Hf and (Al+12.5 at.%Zn)3Hf Prepared by MA and SPS

2004 ◽  
Vol 449-452 ◽  
pp. 809-812 ◽  
Author(s):  
Chang Won Kang ◽  
Hee Sup Jang ◽  
Seon Jin Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Grain Growth ◽  
Annealing Temperature ◽  
Annealing Temperatures ◽  
Grain Sizes ◽  
Plasma Sintering ◽  
Spark Plasma

Thermal stability and mechanical properties of L12 Al3Hf and (Al+12.5 at.%Zn))3Hf synthesized by mechanical alloying(MA) and spark plasma sintering(SPS) were investigated. Nanocrystalline L12 phase was produced after MA for 8 and 10 hrs in Al3Hf and (Al+12.5 at.%Zn))3Hf powders, respectively. The grain sizes were reduced to about 10 nm in both systems after MA for 20 hrs. After SPS, L12 phase was maintained only in Zn added system. In (Al+12.5 at.%Zn))3Hf, L12 to D023 phase transformation was started at about 850°C and finished at about 1150°C Microhardness was decreased with increasing the annealing temperature while fracture toughness was increased due to the grain growth. Fracture toughness of (Al+12.5 at.%Zn))3Hf was greater than that of Al3Hf in all annealing temperatures. Fracture toughness of (Al+12.5 at.%Zn))3Hf after annealing at 1200°C was about 5.38 MPam1/2.

Effects of Carbon Nanotubes Incorporation on the Grain Growth and Properties of WC/Co Nanocomposites

2005 ◽  
Vol 475-479 ◽  
pp. 989-992 ◽  
Author(s):  
Fa Ming Zhang ◽  
Jian Fei Sun ◽  
Jun Shen
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Binder Phase ◽  
Tubular Structures ◽  
Plasma Sintering ◽  
Mechanical And Physical Properties ◽  
The Matrix ◽  
Spark Plasma

Carbon nanotubes (CNTs) combining unique mechanical and physical properties could offer a kind of nanosized reinforcements for composite materials. Incorporating of CNTs to develop advance engineering composites has become an interesting concept, but the cermets based CNTs composites have been less focused. WC-Co-CNTs nanocomposites were consolidated by spark plasma sintering (SPS) to investigate the effects of CNTs incorporation on the grain growth and mechanical properties of WC-Co nanocomposites. Experimental results show that CNTs could preserve their tubular structures in high temperature SPS process, some CNTs are surviving in the WC-Co fracture surfaces featured bridging and pulling out manner. The interaction between the CNTs and the matrix has a retardation effect of grain growth of WC, but CNTs additions could be resulted in an increase of carbon content in the binder phase that causes enhanced tendency of grain growth, either of which plays the dominated role depending on the CNTs content. The WC-10Co-0.5wt%CNTs nanocomposites possess superior hardness to toughness combinations, which hardness is about 15% and fracture toughness is about 40% higher than that of the pure nano-WC-10Co cermets consolidated under the same process.

Effect of Sintering Pressure on Mechanical Properties of BN-Si3N4 Ceramic Composites Prepared by Spark Plasma Sintering

2016 ◽  
Vol 697 ◽  
pp. 188-192
Author(s):  
Jia Xin An ◽  
Wen Dong Xue ◽  
Feng Rui Zhai ◽  
Ruo Meng Xu ◽  
Jia Lin Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Composite Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

BN-Si3N4 composite ceramic wave-transparent materials with excellent mechanical properties were prepared by spark plasma sintering (SPS) using h-BN and α-Si3N4 powders as raw materials, Al2O3 and Y2O3 as sintering aids. The influence of sintering pressure on density and mechanical properties of BN-Si3N4 composite ceramics were studied. The phases were observed by X-ray diffraction (XRD), and the microstructures were identified by scanning electron microscopy (SEM). The results showed that with the sintering pressure increases, the relative density, bending strength and fracture toughness of the composite ceramics were significantly increased, and the porosity decreased rapidly. The effects of pressure on the properties of the composite ceramics was not significant at >40MPa, so 40MPa is optimal for the composite ceramics to gain good overall performance, i.e. the relative density was 89.1%, the porosity was 2.3%, the bending strength reached 215.4 MPa, and the fracture toughness was 3.1/MPa·m1/2.

Effects of Powder Microscopic Defects on Densification and Mechanical Properties of WC via Spark Plasma Sintering

2021 ◽  
Vol 1016 ◽  
pp. 1770-1777
Author(s):  
Liu Zhu ◽  
Jin Fang Wang ◽  
Zhi Biao Tu ◽  
Na Xue ◽  
Wei Wei Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Free Energy ◽  
Composite Powder ◽  
Sintering Temperature ◽  
Chemical Activation ◽  
Activation Technique ◽  
Specific Chemical ◽  
Plasma Sintering ◽  
Spark Plasma

The WC composite powder was synthesized by a new specific chemical activation technique. A large number of lattice defects such as surface humps, dislocations and stacking fault exist in the surface of the WC powder after chemical activation technique. By using such activated WC powder, the binderless WC cemented carbide with high density (15.54 g/cm3), super hardness (average 26.29 GPa) and excellent fracture toughness (8.9 MPa.m1/2) can be fabricated by SPS at 1700 °C and 50 MPa pressure. The improvement in density, hardness and fracture toughness are respectively 4.5%, 15.3% and 17.1% compared to when using the original WC powder. This improvement is because microscopic defects on the surface of the WC powder can greatly improve surface free energy of the powder, which improves the sintering activity and reduces the sintering temperature of the WC powder.

scholarly journals Powder Metallurgy Processing and Mechanical Properties of Controlled Ti-24Nb-4Zr-8Sn Heterogeneous Microstructures

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1626
Author(s):  
Benoît Fer ◽  
David Tingaud ◽  
Azziz Hocini ◽  
Yulin Hao ◽  
Eric Leroy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Ball Milling ◽  
Processing Route ◽  
Fine Grain ◽  
Plasma Sintering ◽  
3D Network ◽  
Spark Plasma ◽  
Powder Particles ◽  
Heterogeneous Microstructures

This paper gives some insights into the fabrication process of a heterogeneous structured β-metastable type Ti-24Nb-4Zr-8Sn alloy, and the associated mechanical properties optimization of this biocompatible and low elastic modulus material. The powder metallurgy processing route includes both low energy mechanical ball milling (BM) of spherical and pre-alloyed powder particles and their densification by Spark Plasma Sintering (SPS). It results in a heterogeneous microstructure which is composed of a homogeneous 3D network of β coarse grain regions called “core” and α/β dual phase ultra-fine grain regions called “shell.” However, it is possible to significantly modify the microstructural features of the alloy—including α phase and shell volume fractions—by playing with the main fabrication parameters. A focus on the role of the ball milling time is first presented and discussed. Then, the mechanical behavior via shear tests performed on selected microstructures is described and discussed in relation to the microstructure and the probable underlying deformation mechanism(s).

Microstructure and Mechanical Properties of Spark-Plasma-Sintered SiC-TiC Composites

2005 ◽  
Vol 287 ◽  
pp. 335-339 ◽  
Author(s):  
Kyeong Sik Cho ◽  
Kwang Soon Lee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Argon Atmosphere ◽  
Full Density ◽  
Plasma Sintering ◽  
Spark Plasma

Rapid densification of the SiC-10, 20, 30, 40wt% TiC powder with Al, B and C additives was carried out by spark plasma sintering (SPS). In the present SPS process, the heating rate and applied pressure were kept at 100°C/min and at 40 MPa, while the sintering temperature varied from 1600-1800°C in an argon atmosphere. The full density of SiC-TiC composites was achieved at a temperature above 1800°C by spark plasma sintering. The 3C phase of SiC in the composites was transformed to 6H and 4H by increasing the process temperature and the TiC content. By tailoring the microstructure of the spark-plasma-sintered SiC-TiC composites, their toughness could be maintained without a notable reduction in strength. The strength of 720 MPa and the fracture toughness of 6.3 MPa·m1/2 were obtained in the SiC-40wt% TiC composite prepared at 1800°C for 20 min.

Fabrication of MgO/Graphene Composites by Combustion Synthesis and Spark Plasma Sintering

2018 ◽  
Vol 281 ◽  
pp. 125-130
Author(s):  
Nan Lu ◽  
Jia Xi Liu ◽  
Gang He ◽  
Jiang Tao Li
Keyword(s):  
Mechanical Properties ◽  
Combustion Synthesis ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
Combustion Reaction ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties ◽  
Plasma Sintering ◽  
Spark Plasma

MgO/Graphene ceramic composites were fabricated by combining combustion synthesis with spark plasma sintering. MgO/Graphene mixture powders were prepared by the combustion reaction between Mg powders and CO2 gas. Dense MgO/Graphene composites were fabricated by spark plasma sintering (SPS) using LiF as the sintering additive. The effect of the sintering temperature on microstructure and mechanical properties of the prepared MgO/Graphene ceramics was discussed. The sintering temperature of the MgO/Graphene mixture powders increased from 900°C to 1300°C. The highest density of 3.43g/cm3 and hardness of 2133MPa were obtained at 1100°C. Compared with monolithic MgO ceramics, the hardness of MgO/Graphene ceramics at the same sintering temperature was increased from 840MPa to 2133MPa.

Spark Plasma Sintering and Characterization of WC-Co-cBN Composites

2014 ◽  
Vol 616 ◽  
pp. 194-198 ◽  
Author(s):  
Jian Feng Zhang ◽  
Rong Tu ◽  
Takashi Goto
Keyword(s):  
Fracture Toughness ◽  
Phase Transformation ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Moderate Pressure ◽  
Plasma Sintering ◽  
Spark Plasma

WC-Co-cBN composites were consolidated by SPS at 1373 to 1673 K under a moderate pressure of 100 MPa. The addition of cBN increased the starting and finishing temperature of shrinkage and decreased the relative density of WC-Co. The relative density of WC-(10-20 vol%) cBN composites was about 97-100% at 1573 K and decreased with increasing the sintering temperature to 1673 K due to the phase transformation of cBN to hBN. The highest hardness and fracture toughness of WC-Co-20 vol% cBN composite sintered at 1573 K were 23.2 GPa and 8.0 MP m1/2, respectively.

scholarly journals Synthesis and Property Characterization of Ternary Laminar Zr2SB Ceramic

2021 ◽  
Author(s):  
Qiqiang Zhang ◽  
Shuai Fu ◽  
Detian Wan ◽  
Yiwang Bao ◽  
Qingguo Feng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Room Temperature ◽  
Thermal Capacity ◽  
Boron Powder ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma ◽  
Property Characterization

Abstract In this paper, Zr2SB ceramics with high relative density (99.03%) and high purity of 82.95 wt% (containing 8.96 wt% ZrB2 and 8.09 wt% zirconium) were successfully synthesized from ZrH2, sublimated sulfur and boron powder by spark plasma sintering at 1300 ℃. The reaction mechanism, microstructures, physical properties and mechanical properties of Zr2SB ceramic were systematically studied. The results show that Zr2SB was obtained by the reaction of zirconium sulfide, zirconium and boron, and ZrB2 coexisted in the sample as a symbiotic impurity phase. The average grain size of Zr2SB was 12.46 μm in length and 5.12 μm in width, and the mean grain sizes of ZrB2 and zirconium impurities were about 300 nm. In terms of physical properties, the measured thermal expansion coefficient was 7.64 × 10-6 K-1 from room temperature to 1200 ℃, and the thermal capacity and thermal conductivity at room temperature were 0.39 J·g−1·K−1 and 12.01 W∙m−1∙K−1, respectively. The room temperature electrical conductivity of Zr2SB ceramic was measured to be 1.74 × 106 Ω−1∙m−1. In terms of mechanical properties, Vickers hardness was 9.86 ± 0.63 GPa under 200 N load, and the measured flexural strength, fracture toughness and compressive strength were 269 ± 12.7 MPa, 3.94 ± 0.63 MPa·m1/2, and 2166.74 ± 291.34 MPa, respectively.

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