scholarly journals The New Complex High-entropy Metal Boron Carbonitride: Microstructure and Mechanical Properties

2021 ◽  
Author(s):  
Jingyi Guan ◽  
Daxin Li ◽  
Zhihua Yang ◽  
Bingzhu Wang ◽  
Delong Cai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Oxide Phase ◽  
Molar Ratio ◽  
Powder Preparation ◽  
Boron Carbonitride ◽  
High Entropy ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering

Abstract Dense (Ta, Nb, Hf, Zr, Ti)(BCN) ceramics (HEC-2) were successfully synthesized via hot-pressing sintering. Results show that sintering temperature and (BCN) addition have great impacts on the microstructure and mechanical properties of HEC-2 ceramics. The microstructure and phase of HEC-2 bulk ceramics were characterized by SEM, XRD and TEM. It was found that high-entropy phase, oxide phase and BN/C phase were precipitated when HEC-2119 powders were sintered at 1900 oC. In addition, the Vicker’s hardness, Bending strength, Bulk density and Open porosity of HEC-2319 ceramic are 24.54 GPa, 522.00 MPa, 9.07 g/cm3 and 0.05%, respectively, whose molar ratio of metal to (BCN) is 1: 0.334. In this work, BCN high-entropy ceramics were sintered on the basis of powder preparation, as provided that sintering temperatures and components have great influences on microstructure and mechanical properties of HEC-2 ceramics.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

scholarly journals Effects of Cr Content on Microstructure and Mechanical Properties of AlCoCrxFeNi High-Entropy Alloy

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Tao-Tsung Shun ◽  
Wei-Jhe Hung
Keyword(s):  
Mechanical Properties ◽  
Molar Ratio ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Cr Content ◽  
Microstructure And Mechanical Properties ◽  
Alloy Hardness ◽  
Fcc Phase ◽  
Bcc Phase ◽  
Feni Alloys

In this study, we investigated the effects of Cr content on the crystal structure, microstructure, and mechanical properties of four AlCoCrxFeNi (x = 0.3, 0.5, 0.7, and 1.0, in molar ratio) high-entropy alloys. AlCoCr0.3FeNi alloy contains duplex phases, which are ordered BCC phase and FCC phase. As the Cr content increases to x = 1.0, the FCC phase disappears and the microstructure exhibits a spinodal structure formed by a BCC phase and an ordered BCC phase. This result indicates that Cr is a BCC former in AlCoCrxFeNi alloys. With increasing Cr content, the alloy hardness increases from HV415 to HV498. AlCoCr0.3FeNi, AlCoCr0.5FeNi, and AlCoCr0.7FeNi exhibit a high compressive fracture strain of about 0.24 because of the formation of the FCC phase in the BCC matrix. Moreover, the highest yield stress of 1394 MPa and compressive strength of 1841 MPa presented by AlCoCrFeNi alloy are due to the existence of a nano-net-like spinodal structure.

Influence of Hot Pressing Sintering Temperature and Time on Microstructure and Mechanical Properties of TiB2/Al2O3 Tool Materials

2012 ◽  
Vol 500 ◽  
pp. 629-633 ◽  
Author(s):  
Mei Lin Gu ◽  
Hong Jing Xu ◽  
Jian Hua Zhang ◽  
Zhi Wei
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Three Point Bending ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Hot Pressing Sintering ◽  
Increasing Temperature

In this paper, a TiB2/Al2O3composite was hot-pressed. The effect of hot pressing parameters on the TiB2/Al2O3composite microstructure and mechanical properties was investigated. The flexural strength and fracture toughness were measured by three point bending testing and direct indentation method, respectively. Experimental results show that the flexural strength decreases consistently with an increase in the sintering time, however, the fracture toughness increases consistently with an increase in the sintering time and sintering temperature. The maximum of the flexural strength is 1072 MPa at 1530 sintering temperature and 60 min sintering time. The microstructures were revealed by means of SEM. The results show that the TiB2grain size and density increases with the increasing temperature and time during hot pressing sintering, which benefits the fracture toughness and flexural strength.

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.

Influence of Hot Pressing Sintering Temperature on the Properties of Low-Density Al0.5NbTa0.8Ti1.5V0.2Zr Refractory High-Entropy Alloy

2021 ◽  
Vol 1016 ◽  
pp. 940-945
Author(s):  
Larissa Moravcikova-Gouvea ◽  
Zuzana Kovacova ◽  
Michael Kitzmantel ◽  
Erich Neubauer ◽  
Vít Jan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
High Hardness ◽  
Full Density ◽  
Homogeneous Distribution ◽  
High Entropy Alloy ◽  
Low Density ◽  
High Entropy ◽  
The Matrix ◽  
Hot Pressing Sintering

In this work, the low-density Al0.5NbTa0.8Ti1.5V0.2Zr RHEA prepared by mechanical alloying combined with hot uniaxial pressing (HP) was investigated. The alloy was subjected to different sintering temperatures on the range of 1200°C up to 1600°C, while keeping a constant densification time. The influence of the increase in sintering temperatures on the RHEAs’ microstructural features, composition and basic mechanical properties was explored by means of x-ray diffraction and scanning electron microscopy, hardness testing, density determination by Archimedes’ principle and elastic moduli by ultrasonic measurements. Full density samples were obtained in all sintering temperatures. The alloy has shown a homogeneous distribution of phases, with presence of dispersed oxides inside the matrix, leading to a fine grain size distribution due to grain-boundary pinning effect, even during the exposure of the alloy at the highest sintering temperature. The mentioned effect is responsible for the achievement of high-hardness in all conditions. Powder metallurgy has been shown to be an advantageous technique for production of alloys for high-temperature applications, as the inherent in-situ formed oxides homogeneously distributed within the matrix may be beneficially used as reinforcement, thus potentially enhancing the mechanical properties of the parts.

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