Effect of Ti(C0.7N0.3) Content on the Microstructure and Mechanical Properties of Ni Bonded NbC-Ti(C0.7N0.3) Based Cermets

2018 ◽  
Vol 274 ◽  
pp. 43-52
Author(s):  
S.G. Huang ◽  
J. Vleugels ◽  
H. Mohrbacher ◽  
M. Woydt
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Grain Size ◽  
Liquid Phase ◽  
Grain Growth ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Partial Replacement ◽  
Microstructural Investigation

NbC-xTi (C0.7N0.3)-10Ni-7.5VC (vol%) based cermets with 0, 5, 10, 15 or 25 vol% Ti (C0.7N0.3) were prepared by conventional pressureles liquid phase sintering at 1420°C in vacuum. Detailed microstructural investigation was performed by SEM, EPMA and XRD analysis. Sintering results indicated that the partial replacement of NbC by Ti (C0.7N0.3) had a significant effect on the carbide grain growth, microstructure, hardness as well as fracture toughness of the fully densified NbC-based cermets. The Ti (C0.7N0.3)-free NbC cermet was composed of homogeneous cubic (Nb,V)C solid solution grains, whereas core-rim structured NbC grains were observed in cermets with Ti (C0.7N0.3) addition. All sintered cermets with  15 vol% Ti (C0.7N0.3) were composed of a fcc solid solution Ni binder and a cubic core-rim solid solution (Nb,V,Ti)C phase with a Nb-rich core and a Ti-rich rim. 3.8 vol% of residual pristine Ti (C0.7N0.3) was present in the cermets with 25 vol% Ti (C0.7N0.3) addition. The 15 vol% Ti (C0.7N0.3) starting powder based cermet exhibited the finest average NbC grain size of 1.48 μm, with a core-rim structure and an interesting combination of hardness (1486 kg/mm2) and fracture toughness (8.7 MPa.m1/2).

Synthesis of WC-10wt.%Co Nanocrystalline Powders with Grain Growth Inhibitor by MTP

2007 ◽  
Vol 534-536 ◽  
pp. 1237-1240 ◽  
Author(s):  
Dong Kyu Park ◽  
Kwang Chul Jung ◽  
Jin Chun Kim ◽  
Sung Yeal Bae ◽  
In Sup Ahn
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Liquid Phase ◽  
Grain Growth ◽  
Growth Inhibitor ◽  
Liquid Phase Sintering ◽  
Nanocrystalline Powders ◽  
Grain Growth Inhibitor ◽  
Nano Crystalline ◽  
Carburizing Process

To improve the fracture strength and wear resistance of WC-Co cemented carbide, various technologies have been developed related producing the nano crystalline. There have been extensive studied conducted to retard grain growth during liquid phase sintering. However, when this inhibitor is added by simple mixing, a micro-pores forms during sintering In this study, WC-Co nanocrystalline powders with grain growth inhibitor in the site were prepared by MTP (Mechano-Thermic carburizing Process) to minimize this formation of micro pores and to retard grain growth effectively during sintering. In addition, then the phase and grain size of WC-Co nanocrystalline powders were evaluated according to the condition of MTP.

scholarly journals Sintering Mechanism, Microstructure Evolution, and Mechanical Properties of Ti-Added Mo2FeB2-Based Cermets

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1889
Author(s):  
Yupeng Shen ◽  
Zhifu Huang ◽  
Lei Zhang ◽  
Kemin Li ◽  
Zhen Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Rupture Strength ◽  
Liquid Phase Sintering ◽  
Maximum Hardness ◽  
Liquid Phases ◽  
Ti Content ◽  
Ti Addition

Four series of Mo2FeB2-based cermets with Ti contents between 0 wt.% and 1.5 wt.% in 0.5 wt.% increments were prepared by in situ reaction and liquid phase sintering technology. Influences of Ti on microstructure and mechanical properties of cermets were studied. It was found that Ti addition increases formation temperatures of liquid phases in liquid-phase stage. Ti atoms replace a fraction of Mo atoms in Mo2FeB2 and the solution of Ti atoms causes the Mo2FeB2 crystal to be equiaxed. In addition, the cermets with 1.0 wt.% Ti content exhibit the smallest particle size. The solution of Ti atoms in Mo2FeB2 promotes the transformation of Mo2FeB2 particles from elongated shape to equiaxed shape. With Ti content increasing from 0 wt.% to 1.5 wt.%, the hardness and transverse rupture strength (TRS) first increase and then decrease. The maximum hardness and TRS occur with 1.0 wt.% Ti content. However, the fracture toughness decreases as Ti content increases. The cermets with 1.0 wt.% Ti content show excellent comprehensive mechanical properties, and the hardness, fracture toughness, and TRS are HRA 89.5, 12.9 MPa∙m1/2, and 1612.6 MPa, respectively.

Microstructure of TiB2 liquid phase sintered with Ni3Al

1983 ◽  
Vol 41 ◽  
pp. 62-63
Author(s):  
P. Angelini ◽  
J. Bentley ◽  
C. B. Finch ◽  
P. S. Sklad
Keyword(s):  
Solid Solution ◽  
Thermal Expansion ◽  
Liquid Phase ◽  
Electrical Properties ◽  
Grain Growth ◽  
Hot Pressing ◽  
Liquid Phase Sintering ◽  
Intergranular Phase ◽  
Phase Development ◽  
Al Powder

TiB2 is a ceramic material which possesses exceptional thermal, chemical, and electrical properties. Commercial powders can be formed into bulk pieces by hot pressing at temperatures near 2000°C. However, this produces excessive grain growth which can lead to cracking and low mechanical integrity due to the relatively large anisotropic thermal expansion of the TiB2 grains. Liquid phase sintering can be used to produce structural forms of TiB2 by hot pressing at temperatures near 1450°C. This process limits the TiB2 grain growth but introduces an intergranular phase. Previous work used Ni as a binder and under most hot-pressing conditions this resulted in the formation of a Ni3B intergranular phase. Additional binders are being considered to understand the phase development during liquid-phase sintering and to improve the properties of the bonded TiB2 forms.The present research concerns the use of Ni3Al as a binder for TiB2. The Ni3Al powder was a physical mixture of 32 wt % NiAl and 68 wt % of a solid solution of 95 at. % Ni with 5 at. % Al powders.

Effect of (Ni,Mo) and (W,Ti)C on the Microstructure and Mechanical Properties of TiB2 Ceramic Tool Materials

2012 ◽  
Vol 723 ◽  
pp. 233-237 ◽  
Author(s):  
Tong Chun Yang ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou ◽  
Hong Tao Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties

TiB2-(W,Ti)C composites with (Ni,Mo) as sintering additive have been fabricated by hot-pressing technique, and the microstructure and mechanical properties of the composites have been investigated. (Ni,Mo) promotes grain growth of the composites. In the case of 7vol.% (Ni,Mo), the grain size decreases consistently with an increase in the content of (W,Ti)C. When the proper content of (W,Ti)C is added to TiB2 composites, the growth of matrix grains is inhibited and the mechanical properties of the composites are improved. The best mechanical properties of the composites are 1084.13MPa for three-point flexural strength, 7.80MPa•m 1/2 for fracture toughness and 17.92GPa for Vickers hardness.

Influence of Al2O3 Addition on the Microstructure and Mechanical Properties of Pressureless Sintered Ce-TZP

2005 ◽  
Vol 492-493 ◽  
pp. 783-0 ◽  
Author(s):  
Shui Gen Huang ◽  
Lin Li ◽  
Jef Vleugels ◽  
Pei Ling Wang ◽  
Omer Van der Biest
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Good Combination ◽  
Al2o3 Content ◽  
Pressureless Sintering ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties

Mixtures of 12 mol% CeO2-stabilised ZrO2 with 5 to 20 wt % Al2O3 were prepared and densified through pressureless sintering in air at 1450° C for 1 to 4 h. The influence of the Al2O3 content and sintering time on the phase constitution, microstructure and mechanical properties of the as-sintered composites were investigated. Fully dense Ce-TZP/Al2O3 ceramics with a good combination of hardness and fracture toughness can be obtained by pressureless sintering in air for only 1 h. The addition of Al2O3 to Ce-TZP improves the mechanical properties and suppresses ZrO2 grain growth. The average ZrO2 grain size increases with increasing sintering time and decreasing Al2O3 content. This leads to an increase in toughness. An excellent fracture toughness of 14.3 MPam1/2 in combination with a Vickers hardness of 9.14 GPa was obtained for 12 mol % CeO2-TZP with 5 wt % Al2O3, sintered for 4 h.

The Influence of Processing Parameters on Mechanical Properties of Spark Plasma Sintered Chromium Carbide Based Cermets

2017 ◽  
Vol 267 ◽  
pp. 162-166
Author(s):  
Kristjan Juhani ◽  
Jüri Pirso ◽  
Marek Tarraste ◽  
Mart Viljus ◽  
Sergei Letunovitš
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Chromium Carbide ◽  
Processing Parameters ◽  
Liquid Phase Sintering ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintered Chromium

Present paper discusses the influence of spark plasma sintering (SPS) on the microstructure and perfomances of chromium carbide based cermets. The effect of SPS parameters (temperature, pressure) is discussed. It is shown that SPS enables to produce more fine grained chromium carbide based cermets compared to conventional liquid phase sintering. Hardness and fracture toughness are exhibited.

scholarly journals Densification and Mechanical Properties of Alumina Ceramics via Two-Step Sintering With Different Holding Times

2021 ◽  
Vol 6 (4) ◽  
pp. 299-304
Author(s):  
Anis Syufina Mohammad Saufi ◽  
Ramesh Singh ◽  
K. Y. Sara Lee ◽  
Tao Wu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Relative Density ◽  
Grain Growth ◽  
Vickers Hardness ◽  
Holding Time ◽  
Alumina Ceramics ◽  
Conventional Sintering ◽  
Viable Approach

The densification and mechanical properties of alumina ceramics were investigated via two-step sintering (TSS) with different holding time. The alumina ceramics were sintered at 1450 °C for 1 min during the first stage, followed by sintering at 1350 °C with different holding times (2-24h). Conventional sintering (CS) was also performed on the alumina ceramics at 1450 °C for 2 h for comparison purpose. It was found that dense alumina with a relative density above 98% could be attained when TSS with a holding time of more than 12 h. The samples exhibited Vickers hardness between 5-8 GPa and fracture toughness of about 6 MPa.m1/2. In contrast, conventional sintered alumina yielded low relative density (85%), large grain size (2 μm), low Vickers hardness (4.23 GPa) and fracture toughness (4.73 MPa.m1/2). This study revealed that TSS is a viable approach in aiding densification, suppressing grain growth, and improving the mechanical properties of alumina ceramics.

Sintering + HIP of Ultrafine WC-Co Hardmetals

2007 ◽  
Vol 560 ◽  
pp. 121-126
Author(s):  
A. Ordóñez ◽  
R. González ◽  
J.M. Sánchez
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Liquid Phase ◽  
Eutectic Point ◽  
Liquid Phase Sintering ◽  
Growth Inhibitors ◽  
Vacuum Sintering ◽  
Porosity Reduction ◽  
Different Temperatures ◽  
Strength Improvement

This work analyses the changes induced on the microstructure and mechanical properties of ultrafine (0.2 and 0.4 μm) hardmetal grade WC-7wt.% Co by HIP after vacuum sintering. A large HIP pressure (155 MPa) is applied to the ultrafine hardmetal system at different temperatures (1000, 1200 and 1400 °C). The well-known correlation between porosity reduction and fracture strength improvement is confirmed. Residual porosity left after liquid phase sintering is removed more effectively at HIP temperatures above the eutectic point of the alloy (1400 °C). In the absence of grain growth inhibitors, hardness decreases continuously, and WC-Co ultrafine microstructure coarsens as HIP temperature rises. However, for specimens containing VC and Cr3C2 additions, hardness increases as HIP temperature rises from 1200 to 1400 °C. It is proposed that this anomalous trend (confirmed by grain size observations) is related to the activation of coalescence mechanisms during solid state HIPing, which are inhibited by the presence of a liquid phase.

Research on the Ceramic Sintering Grain Growth Model

2016 ◽  
Vol 852 ◽  
pp. 374-377
Author(s):  
Shui Qing Xiao ◽  
Shang Hua Wu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Growth ◽  
Growth Model ◽  
Solid Phase ◽  
Ceramic Materials ◽  
Liquid Phase Sintering ◽  
Grain Growth Model ◽  
Ceramic Sintering ◽  
Material Grain Size

Mechanical properties of ceramic materials are closely related to the grain size, and control the ceramic material grain size is the key to increase mechanical properties of materials. Study on the theory of ceramic sintering grain growth model, such as solid phase sintering, liquid phase sintering and master sintering curve (MSC) and so on. Grain growth model not only can be used to guide the actual production design, but also can be used as a computer simulation tools. It is suggest that before use any grain growth model must modify their express from traditional model, and check the equation is correct that it is agree with the result of re-experiment.

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