scholarly journals C0.3N0.7Ti-SiC Toughed Silicon Nitride Hybrids with Non-Oxide Additives Ti3SiC2

2020 ◽  
Author(s):  
Heng Luo ◽  
Chen Li ◽  
Lianwen Deng ◽  
Yang Li ◽  
Peng Xiao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Crack Deflection ◽  
Crack Branching ◽  
Hot Press ◽  
Pull Out ◽  
Si3n4 Ceramics

In-situ grown C0.3N0.7Ti and SiC, which derived from non-oxide additives Ti3SiC2, are proposed to densify silicon nitride (Si3N4) ceramics with enhanced mechanical performance. Remarkable increase of density from 79.20% to 95.48% could be achieved for Si3N4 ceramics with 5vol% Ti3SiC2. The capillarity of decomposed Si from Ti3SiC2, and in-situ reaction between nonstoichiometric TiCx and Si3N4 were believed to be responsible for densification of Si3N4 ceramics. An obvious enhancement of flexural strength and fracture toughness for Ti3SiC2 doped Si3N4 ceramics was observed. The maximum flexural strength of 795 MPa for Si3N4 composites with 5vol% Ti3SiC2 and maximum fracture toughness of 6.97 MPa.m1/2 for Si3N4 composites with 20vol% Ti3SiC2 are achieved when mixed powders are hot-press sintered at 1700℃. Pull out of elongated Si3N4 grains, crack bridging, crack branching and crack deflection were demonstrated to dominate enhance fracture toughness of Si3N4 composites.

scholarly journals C0.3N0.7Ti-SiC Toughed Silicon Nitride Hybrids with Non-Oxide Additives Ti3SiC2

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1428
Author(s):  
Heng Luo ◽  
Chen Li ◽  
Lianwen Deng ◽  
Yang Li ◽  
Peng Xiao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Sintering Temperature ◽  
Hot Press ◽  
Pull Out ◽  
Hot Press Sintering ◽  
Si3n4 Ceramics

In situ grown C0.3N0.7Ti and SiC, which derived from non-oxide additives Ti3SiC2, are proposed to densify silicon nitride (Si3N4) ceramics with enhanced mechanical performance via hot-press sintering. Remarkable increase of density from 79.20% to 95.48% could be achieved for Si3N4 ceramics with 5 vol.% Ti3SiC2 when sintered at 1600 °C. As expected, higher sintering temperature 1700 °C could further promote densification of Si3N4 ceramics filled with Ti3SiC2. The capillarity of decomposed Si from Ti3SiC2, and in situ reaction between nonstoichiometric TiCx and Si3N4 were believed to be responsible for densification of Si3N4 ceramics. An obvious enhancement of flexural strength and fracture toughness for Si3N4 with x vol.% Ti3SiC2 (x = 1~20) ceramics was observed. The maximum flexural strength of 795 MPa for Si3N4 composites with 5 vol.% Ti3SiC2 and maximum fracture toughness of 6.97 MPa·m1/2 for Si3N4 composites with 20 vol.% Ti3SiC2 are achieved via hot-press sintering at 1700 °C. Pull out of elongated Si3N4 grains, crack bridging, crack branching and crack deflection were demonstrated to dominate enhance fracture toughness of Si3N4 composites.

Indentation Fracture Toughness of Al2O3 + GPLs and Si3N4 + GPLs Systems

2016 ◽  
Vol 368 ◽  
pp. 166-169 ◽  
Author(s):  
Richard Sedlák ◽  
Alexandra Kovalčíková ◽  
Monika Tatarková ◽  
Pawel Rutkowski ◽  
Ján Dusza
Keyword(s):  
Fracture Toughness ◽  
Ceramic Composites ◽  
Crack Deflection ◽  
Crack Branching ◽  
Hot Press ◽  
Indentation Fracture ◽  
Pull Out ◽  
Crack Type ◽  
Indentation Fracture Toughness ◽  
Scanning Electron

The influence of 1 wt.% and 2 wt.% of graphene platelets (GPLs) addition on indentation fracture toughness (IF) of aluminium oxide (Al2O3) and silicon nitride (Si3N4) based composites has been investigated and compared to the monoliths. Ceramic composites reinforced with GPLs were prepared using hot-press processing technology. Microstructures were observed at fracture surfaces by scanning electron microscopy (SEM). Crack type identification was performed by gradually polishing of the indentation surface and mechanical properties of both systems were measured. Indentation fracture toughness was calculated by various methods and R-curves were prepared. The main activated toughening mechanisms, responsible for the increased fracture toughness are crack deflection, crack branching and crack bridging in the forms of graphene sheet pull-out or graphene necking.

scholarly journals Reinforcing Mechanisms of Graphene and Nano-TiC in Al2O3-Based Ceramic-Tool Materials

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1815 ◽  
Author(s):  
Zhefei Sun ◽  
Jun Zhao ◽  
Xuchao Wang ◽  
Enzhao Cui ◽  
Hao Yu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Crack Deflection ◽  
Crack Branching ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Pull Out ◽  
Quantitative Studies ◽  
Reinforcing Effects

Graphene and nano-TiC, which have good reinforcing effects on Al2O3-based ceramic-tool materials, are generally used as additive phases for ceramics. In this study, nine kinds of samples were sintered, to investigate the effects of graphene and nano-TiC on the reinforcing mechanisms of Al2O3-based ceramics. The experimental results indicated that adding 0.5 vol% graphene and 10 vol% nano-TiC can obtain the optimum flexural strength, fracture toughness, and Vickers hardness, which were 705 ± 44 MPa, 7.4 ± 0.4 MPa m1/2, and 20.5 ± 0.8 GPa, respectively. Furthermore, the reinforcing mechanisms of crack bridging, pull-out of graphene, and pull-out of nano-TiC are identified, which are contributed to improving the mechanical properties of ceramics. Meanwhile, other reinforcing mechanisms induced by graphene (graphene break, crack guiding, and 3D propagation) and nano-TiC (crack branching, crack deflection, and peeling) are discussed. These reinforcing mechanisms are coupled together, while decoupling is hard to work out. Thus, further quantitative studies of reinforcing effects of graphene and nano-TiC on Al2O3-based ceramic-tool materials are necessary to be carried out.

scholarly journals Fabrication and mechanical properties of Al2O3/TiAl in situ composites doped with Nb2O5

2015 ◽  
Vol 47 (3) ◽  
pp. 311-317 ◽  
Author(s):  
F. Wang ◽  
N. Fan ◽  
J. Zhu ◽  
H. Jiang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Press ◽  
Dispersion Method ◽  
Powder Mixtures ◽  
In Situ Composites ◽  
Microstructures And Mechanical Properties

Al2O3/TiAl composites were successfully fabricated from powder mixtures of Ti, Al, TiO2, Cr2O3 and Nb2O5 by a hot-press-assisted exothermic dispersion method. The effect of the Cr2O3 and Nb2O5 addition on the microstructures and mechanical properties of Al2O3/TiAl composites was characterized. The results showed that the specimens are mainly composed of TiAl, Ti3Al, Al2O3, NbAl3 and Cr2Al. The Vicker-hardness and density of Al2O3/TiAl composites increase gradually with the increase of Nb2O5 content. When the Nb2O5 content was 6.54 wt %, the flexural strength and fracture toughness of the composites have a maximum values of 789.79 MPa and 9.69 MPa?m1/2, respectively. The improvement of mechanical properties is discussed in detail.

Microstructures and Mechanical Properties of B4C-TiB2 Composite Prepared by Hot Pressure Sintering

2010 ◽  
Vol 434-435 ◽  
pp. 50-53 ◽  
Author(s):  
Xin Yan Yue ◽  
Shu Mao Zhao ◽  
Liang Yu ◽  
Hong Qiang Ru
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Microstructural Analysis ◽  
Crack Deflection ◽  
Second Phase ◽  
Fine Grain ◽  
Pull Out ◽  
Microstructures And Mechanical Properties

B4C-TiB2 composite was prepared using hot pressure sintering. The microstructures and mechanical properties of the B4C-TiB2 composite were investigated. The B4C-TiB2 composite with 43 mass % TiB2 showed the optimized properties. The relative density, hardness, flexural strength and fracture toughness of that were 98.2 %, 25.9 GPa, 458 MPa and 8.7 MPa•m1/2, respectively. A number of toughening mechanisms, including fine grain, crack deflection and grain pull-out, were observed during microstructural analysis of the composite. The fracture mode of the B4C-TiB2 composite was greatly affected by the existence of the second phase of TiB2.

Microstructure and Mechanical Properties of Al2O3/NiAl In Situ Composites by Hot-Press-Aided Reaction Synthesis

2012 ◽  
Vol 581-582 ◽  
pp. 548-551 ◽  
Author(s):  
Guo Quan Qi ◽  
Feng Shou Shangguan ◽  
Li Neng Yang ◽  
Qiang Bai ◽  
Gang Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Elemental Powder ◽  
Reaction Synthesis ◽  
Hot Press ◽  
Dispersion Method ◽  
Powder Mixtures

Al2O3/NiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with elemental powder mixtures of Ni, Al, NiO. The content of Al2O3 on the microstructures and mechanical properties of Al2O3/NiAl composites has been characterized. The results show that the Vickers hardness, flexural strength and fracture toughness of the composites increase with increasing Al2O3 content. When the Al2O3 content is 15 wt %, the flexural strength and the fracture toughness peaked at 765 MPa and 9.67 MPa•m 1/2, respectively. The improvement of mechanical properties is associated with a more homogeneous and finer microstructure developed by addition of Al2O3.

Effect of Carbon Addition on the Microstructure and Mechanical Properties of the In Situ Formed TiAl/Ti2AlC Composites

2011 ◽  
Vol 217-218 ◽  
pp. 680-683
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Synthesis Method ◽  
Elemental Powder ◽  
Hot Press ◽  
Carbon Addition ◽  
Rockwell Hardness ◽  
Powder Mixtures

TiAl/Ti2AlC composites were successfully fabricated by hot-press-assisted reactive synthesis method from elemental powder mixtures of Ti, Al and C. The effect of C addition on the microstructures and mechanical properties of TiAl/Ti2AlC composites was investigated in detail. The results show that the Rockwell hardness, flexural strength and fracture toughness of the composites are modified by incorporation of in situ formed Ti2AlC. When the C content was 0.44 wt %, the flexural strength and the fracture toughness reach the maximum values of 658.7 MPa and 10.03 MPa•m1/2, respectively. The reinforcing mechanism was also discussed.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3/TiAl In-Situ Composites

2011 ◽  
Vol 695 ◽  
pp. 227-230
Author(s):  
Liu Yi Xiang ◽  
Fen Wang ◽  
Jian Feng Zhu ◽  
Xiao Feng Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Rockwell Hardness ◽  
Dispersion Method ◽  
Powder Mixtures

Al2O3/TiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with powder mixtures of Ti, Al, TiO2and Cr2O3as raw materials. The effect of sintering temperature on the microstructures and mechanical properties of Al2O3/TiAl composites has been investigated. The results show that the Rockwell hardness and density of the composites increased with increasing sintering temperature. But the flexural strength and fracture toughness peaked at 825 MPa and 7.29 MPa·m1/2, respectively, when the sintering temperature reached to1300 °C.

Strength Degradation Flaws in the Liquid-Phase-Sintered SiC Based Ceramics

2009 ◽  
Vol 409 ◽  
pp. 350-353
Author(s):  
Alexandra Kovalčíková ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Crack Deflection ◽  
Liquid Phase Sintering ◽  
Crack Branching ◽  
Mechanical Interlocking ◽  
Heat Treated

The effect of the heat treatment on the fracture toughness and flexural strength of the silicon carbide – silicon nitride composites prepared by liquid-phase-sintering was investigated. The results were compared to those obtained for a reference silicon carbide material, prepared by the same fabrication route. The fracture toughness increased from 3.19 to 5.15 MPa.m1/2 due to the toughening mechanisms (crack deflection, mechanical interlocking, crack branching) occurring in the heat treated materials during the crack propagation. However, the flexural strength decreased after the heat treatment of the experimental materials. The strength of the investigated materials was degraded by the presence of processing flaws mainly in the form of pores, clusters of pores, and SiC agglomerates.

Effect of Si Addition on the Microstructures and Mechanical Properties of TiAl Intermetallics

2011 ◽  
Vol 239-242 ◽  
pp. 413-416 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Shao Dan Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Press ◽  
The Matrix ◽  
Press Method ◽  
Microstructures And Mechanical Properties ◽  
Si Content ◽  
Si Addition

TiAl/Ti5Si3 in situ composites were successfully fabricated by reactive hot-press method from powder mixtures of Ti, Al and Si. The influence of the Si addition on the microstructures and mechanical properties of TiAl/Ti5Si3 composites was investigated in detail. The results show that an appropriate amount of addition of Si refined the matrix structure obviously due to the in situ formed Ti5Si3, and as a result, the flexural strength and fracture toughness of the composites are modified. When the Si content is 1.82 wt %, the flexural strength and the fracture toughness reach the maximum value of 685.67 MPa and 9.02 MPa·m1/2, respectively. The enhancing mechanism was also discussed.

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