Densification of Sr-Mg Doped SiAlONs with GPS and SPS

2007 ◽  
Vol 554 ◽  
pp. 95-100 ◽  
Author(s):  
S. Kurama ◽  
Mathias Herrmann
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Phase 1 ◽  
Densification Process ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Lower Temperature ◽  
The Stability ◽  
Thermal Stability Of ◽  
Mg Doped

At temperature above 1200°C, the thermal stability of α-SiAlON phases has been debated since 1992; however, it has been discussed if any α-SiAlON phase can be formed in Ce, La, Eu and Sr-doped SiAlON systems. In our previous studies it was shown that the use of Mg-Ce and Mg-Sr elements as dopants SiAlON compositions, in which all elements just have very low or no stability in the α-SiAlON structure, would promote the stability of Mg-Ce elements in the α- SiAlON phase [1, 2]. However, in Mg-Sr systems, it was obtained that Mg2+ is predominantly incorporated in α-SiAlON structure whereas Sr2+ mainly remains in the grain boundaries [2]. In this study, by applying spark plasma sintering (SPS) (at 1400-1700°C) and post-sintering thermal heat treatment (at 1500°C for 5 hrs and 1700°C for 2hrs) Mg or Mg-Sr doped SiAlON (50:50 mole ratios) ceramics were prepared. The results were compared with GPS sintered samples data. The effect of sintering temperature on densification process, phase transformation, microstructure and mechanical properties of samples were investigated. The results showed that by using SPS, Sr-Mg doped samples can be sintered at lower temperature (at 1600°C) than at GPS (at 1800°C) and it has no Sr-doped grain boundary phases.

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.

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.

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.

Fabrication of TiAl Intermetallic by Spark Plasma Sintering

2007 ◽  
Vol 336-338 ◽  
pp. 1050-1052 ◽  
Author(s):  
Hai Tao Wu ◽  
Yun Long Yue ◽  
Wei Bing Wu ◽  
Hai Yan Yin
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Three Point Bending ◽  
The Poor ◽  
High Relative Density ◽  
Plasma Sintering ◽  
Spark Plasma

The γ-TiAl intermetallic compounds were produced at the temperature ranging from 850°C to 1050°C by the Spark Plasma Sintering (SPS) process. The effects of sintering temperature and holding time on the mechanical properties of γ-TiAl intermetallic compounds were investigated. The γ-TiAl intermetallic compounds sintered at 1050°C for 10 min showed a high relative density more than 98%, and had the best three-point bending strength of 643MPa, fracture toughness of 12 MPa·m1/2 and microhardness of 560MPa. The microstructural observations indicated typical characteristics of intergranular fracture, which meant the poor ductility of γ-TiAl intermetallic compounds.

Microstructure and Properties of Spark Plasma Sintering AlN/BN Ceramics

2006 ◽  
Vol 313 ◽  
pp. 105-108 ◽  
Author(s):  
Lian Meng Zhang ◽  
Mei Juan Li ◽  
Qiang Shen ◽  
T. Li ◽  
M.Q. Yu
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Mechanical Strength ◽  
Spark Plasma Sintering ◽  
Volume Fraction ◽  
Sintering Temperature ◽  
Composite Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Full Densification

Aluminum nitride-boron nitride (AlN/BN) composite ceramics were prepared by spark plasma sintering (SPS). The sintering behaviors of AlN/BN composites with 5~15% volume fraction of BN were studied. The influences of BN content, as well as the sintering temperature on the density, microstructure, mechanical strength, thermal conductivity and machinability of the composites were also investigated. The results showed that the full densification of AlN/BN composite ceramics could be realized by SPS technique at the temperature no higher than 1800°C for 3 minutes. The thermal conductivity of AlN/BN composites is in the range of 66~79W/mK, and AlN/BN composites can be cut or drilled by carbides or even steel tools when BN content is 15% volume fraction. The mechanical strength of AlN/BN composites is about 330MPa and is not remarkably affected by the addition of BN. The improvement of mechanical properties of AlN/BN composite ceramics is due to the fine and homogenous microstructure developed in the SPS process.

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