scholarly journals Improvement of the mechanical properties of spark plasma sintered hap bioceramics by decreasing the grain size and by adding multi-walled carbon nanotubes

2013 ◽  
Vol 45 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Dj. Veljovic ◽  
G. Vukovic ◽  
I. Steins ◽  
E. Palcevskis ◽  
P.S. Uskokovic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Grain Size ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Walled Carbon Nanotubes

Composites based on HAP and oxidized multi-walled carbon nanotubes (o-MWCNT) and monophase HAP materials were processed by spark plasma sintering. Starting from stoichiometric nano-sized HAP powder, monophase bioceramics were obtained with a density close to the theoretical one and with an average grain size of several hundred nanometers to micron dimensions. It was shown that decreasing the sintering temperature resulted in a decrease of the grain size, which affected an increase in the fracture toughness and hardness. The fracture toughness of an HAP/ o-MWCNT bioceramic processed at 900?C for only 5 min was 30 % higher than that of monophase HAP materials obtained under the same conditions. The addition of MWCNT during SPS processing of HAP materials caused a decrease in the grain size to the nano-dimension, which was one of the reasons for the improved mechanical properties.

Reinforcement of B4C Ceramics with Multi-Walled Carbon Nanotubes

2009 ◽  
Vol 66 ◽  
pp. 41-44 ◽  
Author(s):  
Fan Zhang ◽  
Zheng Yi Fu ◽  
Jin Yong Zhang ◽  
Hao Wang ◽  
Wei Min Wang ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Composite Materials ◽  
Grain Boundaries ◽  
Spark Plasma Sintering ◽  
Plasma Sintering ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Walled Carbon Nanotubes

Here we have prepared B4C/CNTs composites using the spark-plasma sintering (SPS) method. Mechanical property measurements reveal obvious enhancement confirming the fabrication of true B4C/CNTs composite materials with improved toughness properties.The addition of 1wt% CNTs in the B4C increased the fracture toughness by about 1.6 times from 2.5 to 4 MPa.m1/2 because the CNTs presented at the B4C grain boundaries, made the length of cracks shorten.

Effect of Sintering Schedule on the Microstructure of Carbon Nanotubes Reinforced Alumina Fabricated by SPS Method

2009 ◽  
Vol 66 ◽  
pp. 288-291
Author(s):  
Li Wei Huang ◽  
Zheng Yi Fu ◽  
Jin Yong Zhang ◽  
Wei Min Wang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Raman Spectrum ◽  
Sintering Temperature ◽  
Alumina Ceramics ◽  
Pure Alumina ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Method

Carbon nanotubes reinforced alumina was fabricated by spark plasma sintering method. When adding 0.2wt% nanotubes, the fracture toughness of the composites prepared increases 19% compared with the pure alumina ceramics. The effect of sintering schedule on microstructure and mechanical properties is investigated systematically. Microstructure studies reveal that at high sintering temperature, the nanotubes tend to gather in the gaps surrounded by three or more grains in a flocculent state, which leads to poor mechanical properties. Raman spectrum indicates that long sintering duration may cause serious nanotubes destruction and lower the mechanical properties.

scholarly journals Enhancement of Electrical Conductivity of Aluminum-Based Nanocomposite Produced by Spark Plasma Sintering

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1150
Author(s):  
Nicolás A. Ulloa-Castillo ◽  
Roberto Hernández-Maya ◽  
Jorge Islas-Urbano ◽  
Oscar Martínez-Romero ◽  
Emmanuel Segura-Cárdenas ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Spark Plasma Sintering ◽  
Experimental Tests ◽  
Powder Morphology ◽  
Plasma Sintering ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Ball Milling Technique ◽  
Walled Carbon Nanotubes

This article focuses on exploring how the electrical conductivity and densification properties of metallic samples made from aluminum (Al) powders reinforced with 0.5 wt % concentration of multi-walled carbon nanotubes (MWCNTs) and consolidated through spark plasma sintering (SPS) process are affected by the carbon nanotubes dispersion and the Al particles morphology. Experimental characterization tests performed by scanning electron microscopy (SEM) and by energy dispersive spectroscopy (EDS) show that the MWCNTs were uniformly ball-milled and dispersed in the Al surface particles, and undesirable phases were not observed in X-ray diffraction measurements. Furthermore, high densification parts and an improvement of about 40% in the electrical conductivity values were confirmed via experimental tests performed on the produced sintered samples. These results elucidate that modifying the powder morphology using the ball-milling technique to bond carbon nanotubes into the Al surface particles aids the ability to obtain highly dense parts with increasing electrical conductivity properties.

Structure, phase composition and mechanical properties of composites based on ZrO2 and multi-walled carbon nanotubes

2020 ◽  
Vol 10 ◽  
pp. 56-68
Author(s):  
A. A. Leonov ◽  
◽  
E. V. Abdulmenova ◽  
M. P. Kalashnikov ◽  
◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Phase Composition ◽  
Zirconium Carbide ◽  
Cubic Phase ◽  
Plasma Sintering ◽  
Multi Walled Carbon Nanotubes ◽  
Spark Plasma ◽  
Walled Carbon Nanotubes ◽  
Tetragonal Phase Transition ◽  
Properties Of Composites

In this work, composites based on yttria-stabilized zirconia (3Y-TZP), with additives of 1, 5 and 10 wt. % multi-walled carbon nanotubes (MWCNTs) were investigated. Samples were obtained by spark plasma sintering at a temperature of 1500 °C. It was found that MWCNTs retain their structure after high-temperature sintering, they are located along the grain boundaries of ZrO2, forming a network structure. Found that the addition of 1 wt. % MWCNTs increase the relative density of the composite from 98.3 % to 99.0 %. It is noted that nanotubes can significantly affect the phase composition of composites. Additive 5 wt. % MWCNT partially limits the monoclinic-tetragonal phase transition of ZrO2, and the addition of 10 wt. % MWCNTs leads to the formation of a cubic phase of zirconium carbide. It was found that the fracture toughness of the composite with 10 wt. % MWCNTs increases from 4.0 to 5.7 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.

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.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Nanocrystalline Aluminum 5083 Alloy

2015 ◽  
Vol 782 ◽  
pp. 113-118
Author(s):  
Ying Mei Teng ◽  
Zhao Hui Zhang ◽  
Zi Zhou Yuan
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Compressive Strength ◽  
Sintering Temperature ◽  
Initial Pressure ◽  
Fine Grain ◽  
Microstructure And Mechanical Properties ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Bulk Nanocrystalline

The bulk nanocrystalline (NC) aluminum (Al) 5083 was synthesized by spark plasma sintering (SPS) technique with low initial pressure of 1 MPa, high holding pressure of 300 MPa and holding time of 4 min at different sintering temperatures, using surface passivated nanopowders. The effect of sintering temperature on microstructure and mechanical properties of the bulk NC Al 5083 were investigated. Results indicate that the density, grain size, the hardness and the compressive strength of the bulk NC Al 5083 increase with an increase in sintering temperature. The mechanical properties of the material are greatly improved due to the fine grain size. The bulk NC Al 5083 sintered at 723 K has the highest micro-hardness of 2.37 GPa and the best compressive strength of 845 MPa.

scholarly journals Influence of the sintering temperature on the microstructure, mechanical properties and densification characteristics of (TiB+TiC)/TC4 composite

2021 ◽  
Author(s):  
Zheng-Yang Hu ◽  
Hai-Chun Peng ◽  
Zhao-Hui Zhang ◽  
Peng Song ◽  
Ming Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Sintering Temperature ◽  
Matrix Composites ◽  
Densification Process ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
B4c Powder

Abstract A hybrid of TiB whiskers and TiC particles reinforced TC4 matrix composites were in-situ synthesized by spark plasma sintering (SPS) using a TC4-0.6wt.% B4C powder mixture at temperatures range from 550°C to 1150°C. The effect of sintering temperature on microstructure, grain size, mechanical properties and densification process of the (TiB+TiC)/ TC4 matrix composites were investigated. The composite sintered at 1050℃ has the highest tensile strength (1129.0 MPa), yield strength (1077.8MPa) and plasticity (7.1%). The aspect ratio of TiB whiskers increases almost linearly below 1050°C and its highest value is 33.2. The grain size of TiC increases with the increase of sintering temperature, and rapid growth occurs in the range of 850°C to 950°C. The composite sintered body appears four shrinkage stages before applying sintering pressure. The corresponding peak temperatures are 663℃, 758℃, 840℃ and 994℃, respectively.

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