Vacuum sintering of plasmochemical powders based on ZrO2 II. Effect of sintering time at high temperature on the phase composition and mechanical properties of ceramics

1995 ◽  
Vol 34 (1-2) ◽  
pp. 26-30
Author(s):  
N. L. Savchenko ◽  
T. Yu. Sablina ◽  
S. N. Kul'kov
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
High Temperature ◽  
Vacuum Sintering ◽  
Sintering Time

Effect of Sintering Time on the Mechanical Properties of WC-8Co Cemented Carbide for Friction Stir Welding Tool

2013 ◽  
Vol 842 ◽  
pp. 220-223
Author(s):  
Bing Liang Liang ◽  
Chen Zhang ◽  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Wen He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Friction Stir Welding ◽  
Rupture Strength ◽  
Cemented Carbide ◽  
Time Range ◽  
Vacuum Sintering ◽  
Friction Stir ◽  
Sintering Time ◽  
Peak Value

WC-8Co cemented carbide specimens were prepared via vacuum sintering. The influences of sintering time on phase composition, microstructure and mechanical properties of WC-8Co cemented carbide were investigated. The results show that dense specimens were obtained in the sintering time range of 15min~60min and the relative density reached over 95%. Only WC and Co3W3C (γ-phase) were detected by XRD without any else phases, even though Co. With the ascended sintering time, the transverse rupture strength (TRS) increased and hardness ascended to peak value and then descended. WC-Co cemented carbide with excellent mechanical properties (HRA>90, TRS~630MPa and KIC>7MPa·m1/2) were obtained. It would be a good candidate for applications of friction stir welding tool.

Effect of Al2O3 nanofibers on compaction, phase composition, and mechanical properties of ZrO2-based composites obtained by vacuum pressureless sintering

2021 ◽  
pp. 132-143
Author(s):  
A. A. Leonov ◽  
E. V. Abdulmenova ◽  
M. P. Kalashnikov ◽  
Jing Li
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Crack Resistance ◽  
Physicomechanical Properties ◽  
Relative Content ◽  
Pressureless Sintering ◽  
Vacuum Sintering ◽  
Tetragonal Modification ◽  
Different Content ◽  
Properties Of Composites

This work studies the effect of the relative content of Al2O3 nanofibers on the compaction, phase composition, and physicomechanical properties of composites based on ZrO2 obtained by free vacuum sintering. It was found that in the process of manufacturing composites, nanofibers are sintered into Al2O3 grains of complex, elongated shape, which form a solid, frame-reinforcing structure. The relative density of composites with 5 wt. % and 10 wt. % of nanofibers, decreases up to 95%. It is shown that in all sintered samples the tetragonal modification of ZrO2 acts as the main phase, and the different content of nanofibers affects the amount of cubic and monoclinic modifications of ZrO2. It was found that addition of 5 wt. % and 10 wt. % of Al2O3 nanofibers increases the microhardness of the composite by 11% and crack resistance by 46%.

Microstructure and Mechanical Properties of SiC Whisker-Reinforced ZrB2 Ultra-High Temperature Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 1730-1732 ◽  
Author(s):  
Ping Hu ◽  
Xing Hong Zhang ◽  
Jie Cai Han ◽  
Song He Meng ◽  
Bao Lin Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Pressing Temperature ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Ultra High Temperature

SiC whisker-reinforced ZrB2 matrix ultra-high temperature ceramic were prepared at 2000°C for 1 h under 30MPa by hot pressing and the effects of whisker on flexural strength and fracture toughness of the composites was examined. The flexural strength and fracture toughness are 510±25MPa and 4.05±0.20MPa⋅m1/2 at room temperature, respectively. Comparing with the SiC particles-reinforced ZrB2 ceramic, no significant increase in both strength and toughness was observed. The microstructure of the composite showed that the SiC whisker was destroyed because the SiC whisker degraded due to rapid atom diffusivity at high temperature. The results suggested that some related parameters such as the lower hot-pressing temperature, a short sintering time should be controlled in order to obtain SiC whiskerreinforced ZrB2 composite with high properties.

Mechanical Properties of WC-Co Cemented Carbide Prepared via Vacuum Sintering

2013 ◽  
Vol 275-277 ◽  
pp. 1917-1920
Author(s):  
Bing Liang Liang ◽  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Nan Jiang
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Relative Density ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
Cemented Carbide ◽  
Vacuum Sintering ◽  
Transverse Rupture Strength ◽  
Temperature Range ◽  
Peak Value

WC-Co cemented carbide specimens were prepared via vacuum sintering. The influences of composition and sintering temperature on phase composition, microstructure and mechanical properties of WC-Co cemented carbide were investigated. The results show that dense specimens were obtained in the sintering temperature range of 1280~1400°C and the relative density reached over 95%. Only WC and Co3W3C (-phase) were detected by XRD without any else phases, even though Co. With the ascended sintering temperature, hardness increased and the transverse rupture strength (TRS) ascended to peak value and then descended. WC-Co cemented carbide with excellent mechanical properties (HRA>90, TRS~700MPa and KIC>10MPa•m1/2) were obtained.

Effect of TiO2 on Mechanical Properties and Microstructure of Magnesium Aluminate Spinel Refractories

2011 ◽  
Vol 284-286 ◽  
pp. 638-641
Author(s):  
Jun Cong Wei ◽  
Xiao Cui Han ◽  
Chun Hui Gao ◽  
Jian Kun Huang ◽  
Jun Bo Tu
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Titanium Dioxide ◽  
Phase Composition ◽  
High Temperature ◽  
Physical Properties ◽  
Room Temperature ◽  
Magnesium Aluminate ◽  
Magnesium Aluminate Spinel

MgO-Al2O3-TiO2 composite refractories were prepared by using magnesium aluminate spinel (MgAl2O4) and titanium dioxide as main starting materials and being sintered at high temperature. The influences of titanium dioxide additions on the room temperature physical properties, phase composition and microstructure were investigated. The phase composition and microstructure were tested by means of XRD and SEM. The results revealed that with increasing TiO2 content, the densification of the composites first increased sand then decreased and maximized at 4% TiO2 loading. This showed appropriate amount of TiO2 could contribute to the sintering of the composites due to the solid solution of TiO2 in magnesium aluminate spinel.

Preparation of NiCr-Sialon-CaF2 Self-Lubricating Die Material and its Friction at High Temperature

2018 ◽  
Vol 279 ◽  
pp. 167-171
Author(s):  
Hao Yang ◽  
Ming Chang ◽  
Hua Jun Wang ◽  
Zhen Рua Yao
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Friction And Wear ◽  
Material System ◽  
Molding Process ◽  
Vacuum Sintering ◽  
Lubricating Material ◽  
Die Material ◽  
Ratio Of Components

In this study, high-temperature self-lubricating material system (NiCr-Sialon-CaF2) was proposed and samples were prepared by powder metallurgy molding process under proper parameters. Samples with excellent properties can be obtained in a vacuum sintering environment of 1200° C for 2 hours and the ratio of components were Sialon ceramic-5 %, CaF2-10 % and NiCr-the rest. By XRD and EPMA test, the phase composition and its ingredients were examined. And after the high temperature properties analysis of samples with different ingredients, such as surface morphology and friction factor, the high temperature friction and wear mechanism of this self-lubricating material system was illustrated.

Improvement of Mechanical Properties of Fe-Cr-Mo-[Cu-Ni]-C Sintered Sintered Steels by Sinter Hardening

2011 ◽  
Vol 672 ◽  
pp. 31-38 ◽  
Author(s):  
Eva Dudrová ◽  
Marco Actis Grande ◽  
Mario Rosso ◽  
Margita Kabátová ◽  
Róbert Bidulský ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Impact Energy ◽  
Vacuum Sintering ◽  
Cooling Rates ◽  
Sintered Steels ◽  
Conventional Sintering

The effect of high temperature sintering and high cooling rate on shifting the microstructural composition to the favourably of martensite-bainite structures and thus effective improvement of mechanical properties of sintered steels based on Astaloy CrL powder with an addition of 1 and 2% Cu or 50% Distaloy AB powder and 0.65% C was investigated. All the systems were processed by both sinter-hardening and conventional sintering. The vacuum sintering at high-temperature of 1240 0C and at common temperature of 1180 0C were integrated with high (6 0C/s), medium (3 0C/s) and slow (0.1 0C/s) cooling rates; conventional sintering at 1180 0C with cooling rate of ~0.17 0C/s was carried out in a N2+10%H2 atmosphere. In dependence on chemical composition, the yield and tensile strengths of 890-1150 MPa and 913-1230 MPa respectively and impact energy of 10-15 J were achieved by sinter-hardening. The yield and tensile strengths are approximately double than those resulting from conventional sintering.

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