scholarly journals Production and Properties of High Entropy Carbide Based Hardmetals

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 271
Author(s):  
Johannes Pötschke ◽  
Manisha Dahal ◽  
Anne Vornberger ◽  
Mathias Herrmann ◽  
Alexander Michaelis
Keyword(s):  
Fracture Toughness ◽  
Titanium Carbide ◽  
Carbide Phase ◽  
Gas Pressure ◽  
Magnetic Saturation ◽  
Binder Phase ◽  
High Entropy ◽  
Saturation Polarization ◽  
Vanadium Titanium ◽  
Gas Pressure Sintering

Dense, high-entropy carbide cobalt-bonded hardmetals with two different compositions, namely (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co and (Ta-Ti-Nb-V-W)C-19.2 vol% Co, were successfully manufactured by gas pressure sintering (SinterHIP) at 1400 °C and 100 bar Ar pressure. The microstructure of these hardmetals consists of a rigid skeletal carbide phase embedded in a tough Co binder phase. EDS mappings showed that the high-entropy carbide phase did not decompose and that a typical hardmetal microstructure was realized. Only in the case of the (Hf-Ta-Ti-Nb-V)C-Co hardmetal was some undissolved TaC and HfO2, as well as some clustered vanadium titanium carbide phase, found, resulting in a split-up of the HEC phase into two very similar HEC phases. This resulted in a reduced hardness to fracture toughness ratio for this composition. Measurements of magnetic saturation polarization showed values between 57.5% and 70% of theoretical magnetic saturation polarization, indicating marginal dissolution of the carbide-forming metal elements in the binder phase. The hardness value HV10 for (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co was 1203 HV10 and 1432 HV10 for (Ta-Ti-Nb-V-W)C-19.2 vol% Co.

Development of α-β SiAlON Ceramics from Different Si3N4 Starting Powders

2008 ◽  
Vol 403 ◽  
pp. 107-108 ◽  
Author(s):  
Nurcan Calis Acikbas ◽  
Ferhat Kara ◽  
Hasan Mandal
Keyword(s):  
Fracture Toughness ◽  
Process Parameters ◽  
Gas Pressure ◽  
Economic Viability ◽  
Si3n4 Powder ◽  
Gas Pressure Sintering

- SiAlON ceramics were produced from different starting Si3N4 powders including β-Si3N4 and α-Si3N4 powders and mixtures of these powders. Gas pressure sintering was used for sintering. After sintering, resultant fracture toughness values were correlated with microstructure and starting powders. By optimizing chemistry and process parameters; - SiAlON ceramics with reasonable fracture toughness can be produced from rather coarse β-Si3N4 powder. This could improve the economic viability of SiAlON ceramics since -Si3N4 powders are less costly.

Thermal Conductivity of Si₃N₄ Ceramics Fabricated From Carbothermal-reduction-derived Powder

2021 ◽  
Author(s):  
Yuelong Wang ◽  
Xingyu Li ◽  
Haoyang Wu ◽  
Baorui Jia ◽  
Deyin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Grain Boundaries ◽  
Carbothermal Reduction ◽  
Secondary Phase ◽  
Gas Pressure ◽  
Gas Pressure Sintering

Abstract Si3N4-based ceramic (Si3N4-5wt%Y2O3-3wt%MgO) was obtained from carbothermal-reduction-derived powder combined with gas pressure sintering. The phase, microstructure, thermal conductivity and mechanical properties of Si3N4 ceramics were comprehensively analyzed. Dense Si3N4 ceramic with uniform grain size was obtained after sintering at 1900°C for 7 h under a N2 pressure of 1.2 MPa. The secondary phase consisted of Y4Si2O7N2 and Y2Si3O3N4 was found to gather around triangular grain boundaries. The thermal conductivity, flexural strength, hardness and fracture toughness of the Si3N4 ceramics were 95.7 W·m-1·k-1, 715 MPa, 17.2 GPa and 7.2 MPa·m1/2, respectively. The results were compared with product derived from commercial powder, the improvement of thermal conductivity (~8.3%) and fracture toughness (~4.3%) demonstrating the superiority of Si3N4 ceramics prepared from carbothermal-reduction-derived powder.

scholarly journals Microstructure and Mechanical Properties of Si3N4-Fe3Si Composites Prepared by Gas-Pressure Sintering

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1206
Author(s):  
Jiasuo Guan ◽  
Laifei Cheng ◽  
Mingxing Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Crack Deflection ◽  
Gas Pressure ◽  
Interface Debonding ◽  
Abnormal Growth ◽  
Pull Out ◽  
Uniform Microstructure ◽  
Microstructure And Mechanical Properties ◽  
Gas Pressure Sintering

Si3N4-Fe3Si composites were prepared using Fe-Si3N4 as the source of Fe3Si by gas-pressure sintering. By adding different amounts of Fe-Si3N4 into the starting powders, Si3N4-Fe3Si composites with various Fe3Si phase contents were obtained. The microstructure and mechanical properties of the composites were investigated. With the increase of Fe-Si3N4 contents, the content and particle size of Fe3Si both increased. When more than 60 wt. % Fe-Si3N4 were added, the abnormal growth of Fe3Si particles occurred and oversized Fe3Si particles appeared, leading to non-uniform microstructures and worse mechanical properties of the composites. It has been found that Fe3Si particles could toughen the composites through particle pull-out, interface debonding, crack deflection, and particle bridging. Uniform microstructure and improved mechanical properties (flexural strength of 354 MPa and fracture toughness of 8.4 MPa·m1/2) can be achieved for FSN40.

Microstructure and Properties of Sintered Reaction Bonded Silicon Nitride with Aligned Whisker Seeds

2005 ◽  
Vol 287 ◽  
pp. 271-276
Author(s):  
Dong Soo Park ◽  
Byung Dong Hahn ◽  
D.-J. Baik
Keyword(s):  
Fracture Toughness ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Flexural Strength ◽  
Tape Casting ◽  
Gas Pressure ◽  
The Other ◽  
Sintering Additives ◽  
Si3n4 Whisker ◽  
Gas Pressure Sintering

Sintered reaction bonded silicon nitride with aligned whisker seeds was prepared by tape casting silicon slurry with 5 wt% b-Si3N4 whisker seeds followed by nitridation and sintering. Three different sintering additives were used for the samples; 7 wt% Y2O3, 6 wt% Y2O3 + 1 wt% Al2O3 and 5 wt% Y2O3 + 2 wt% Al2O3. The sample with 5 wt% Y2O3 + 2 wt% Al2O3 showed the fastest a to b phase transformation after nitridation and the highest fracture toughness and flexural strength after gas pressure sintering among the samples. It also had finer microstructure than the other samples after sintering at 2248 K and at 2273 K. The finer microstructure was related to the faster phase transformation after nitridation, which resulted in the higher flexural strength.

Phase assemblage and properties of a nonoxide composite fabricated by a two-step gas-pressure sintering

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040046
Author(s):  
Li Yin ◽  
Yuxin Wang ◽  
Songtao Jiang ◽  
Zhen He ◽  
Saifang Huang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Mass Loss ◽  
Applied Pressure ◽  
Gas Pressure ◽  
Phase Assemblage ◽  
Intermediate Phases ◽  
Phase Behaviors ◽  
Gas Pressure Sintering ◽  
Sintering Method

In this work, a composite composed of [Formula: see text]-Sialon (Z[Formula: see text]=[Formula: see text]4) and ZrN has been fabricated by a two-step gas-pressure sintering method, and the effects of ZrN content and applied pressure on the phase behavior, densification and mechanical properties have been investigated. The phase behaviors were mainly dependent on the ZrN content and the applied pressure. The composites composed of [Formula: see text]-Sialon (Z[Formula: see text]=[Formula: see text]4), ZrN, 15R-Sialon (0.4 MPa) and 12H-Sialon (0.7 MPa) as major phases, with different intermediate phases depending on the ZrN content. It is revealed that with the two-step sintering technique, a higher applied gas pressure has a positive effect on mass loss, and significantly improved the mechanical properties. The addition of ZrN particles greatly helped the densification behavior, reduced the mass loss, and increased fracture toughness of the composites, but decreased hardness due to formation of intermediate phases and grain coarsening. The addition of ZrN increased the fracture toughness due to the toughening mechanisms of crack branching, crack deflection and crack bridging.

scholarly journals Fracture toughness of Si3N4 processed by gas pressure sintering and hot pressing

2006 ◽  
Vol 9 (2) ◽  
pp. 143-146 ◽  
Author(s):  
Cláudio V. Rocha ◽  
Célio A. Costa
Keyword(s):  
Fracture Toughness ◽  
Hot Pressing ◽  
Gas Pressure ◽  
Gas Pressure Sintering

KENTANIUM K138A

Alloy Digest ◽  
1964 ◽  
Vol 13 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
High Temperature ◽  
Titanium Carbide ◽  
Physical Properties ◽  
Engineering Design ◽  
High Temperatures

Abstract Kentanium K138-A is a high temperature titanium carbide that greatly widens the scope of the engineering design where conditions of intermittent or continuous high temperatures in oxidizing atmospheres are combined with abrasion, and compressive or tensile loads. This datasheet provides information on composition, physical properties, hardness, elasticity, and compressive strength as well as fracture toughness, creep, and fatigue. It also includes information on machining and joining. Filing Code: Ti-40. Producer or source: Kennametal Inc..

FERRO-TIC CS-40

Alloy Digest ◽  
1973 ◽  
Vol 22 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Titanium Carbide ◽  
Martensitic Stainless Steel ◽  
Heat Treating ◽  
High Carbon ◽  
High Chromium ◽  
American Corporation ◽  
Carbide Particles

Abstract FERRO-TIC CS-40 is a tool steel comprising titanium carbide particles bonded in a matrix of high-carbon high-chromium martensitic stainless steel. It is machinable and heat-treatable by conventional means, and is recommended for wear-resistant components where corrosion resistance is a requirement. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: TS-258. Producer or source: Chromalloy American Corporation, Sintercast Division.

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