scholarly journals The Effect of Sintering Temperature on Microstructure and Properties of 94wt% WC - 3wt% TiC - 6wt% Co Sintered by Spark Plasma Sintering

2021 ◽  
Author(s):  
Vahid Aghaali ◽  
Touradj Ebadzadeh ◽  
Seyed Mohammad Zahraee ◽  
Seyed Mohammad Mirkazemi
Keyword(s):  
Fracture Surface ◽  
Tungsten Carbide ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Total Density ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

Abstract Cemented carbide 94wt% WC − 3wt% TiC − 6wt% Co was sintered by spark plasma sintering at various temperatures of 1200, 1300, and 1400°C and the effect of sintering temperature on the microstructure and properties of this type of hard metals, such as total density, apparent density, hardness, and fracture surface were measured and observed using Field Emission-Scanning Electron Microscopy(FE-SEM), Optical Microscopy (OM), X-ray diffractometry (XRD) and mechanical test instruments. The results showed that the apparent density of the samples increased with increasing sintering temperature from 1200℃ to1300℃ from 13.98 g/cm3 to 14.23 g/cm3, respectively. But in the case of sample sintered at 1400℃, the density was reduced to 14.20 g/cm3. Also, micro-hardness results showed that the hardness of sintered samples increased with the increase of sintering temperature. For the sample sintered at 1200°C the hardness value of 1746.41HV was obtained which increased with increasing sintering temperature from 1300℃ to 1400℃ from 2094.33HV to 2280.97HV, respectively. At the optimum sintering temperature, it was found that TiC inhibited the grain growth of tungsten carbide and increased the hardness values. In addition, as expected, the grain growth of tungsten carbide increased with increasing sintering temperatures. Examination of the fracture surface of sintered samples at different temperatures also showed that brittle fracture involves fracture.

scholarly journals Influence of Carbon Diffusion and the Presence of Oxygen on the Microstructure of Molybdenum Powders Densified by SPS

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 948
Author(s):  
Mathias Moser ◽  
Sylvain Lorand ◽  
Florian Bussiere ◽  
Frédéric Demoisson ◽  
Hervé Couque ◽  
...  
Keyword(s):  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Inductively Coupled Plasma ◽  
Sintering Temperature ◽  
Carbon Diffusion ◽  
Inductively Coupled ◽  
Molybdenum Carbides ◽  
Plasma Sintering ◽  
Fine Microstructure ◽  
Spark Plasma

Due to molybdenum’s Body-Centered Cubic (BCC) crystalline structure, its ductile–brittle transition temperature is sensitive to shaping, purity and microstructure. Dense molybdenum parts are usually shaped by the powder metallurgy process. The aim of this work concerns the spark plasma sintering of high-purity powders prepared by inductively coupled plasma. The influence of carbon diffusion and its interaction with oxygen on the density (i.e., the densification stage) and on the microstructure (i.e., the grain growth stage) during spark plasma sintering was investigated. The formation of carbide is usually expected for a sintering temperature above 1500 °C leading to grain growth (e.g., more than 10 times larger than the initial powder grain size after sintering at 1900 °C for 10 min). The brittleness was also affected by the segregation of molybdenum carbides at the grain boundaries (i.e., intergranular brittle fracture). Consequently, to reduce the sintering temperature to below 1500 °C, mechanically activated powders were used. From these milled powders, a dense molybdenum disc (60 mm in diameter and 10 mm in thickness) sintered at 1450 °C under a pressure of 70 MPa for 30 min was obtained. It is composed of a fine microstructure without carbide and oxide, its ductility is close to 13% with a maximum resistance of 550 MPa.

Optical Properties of Transparent MgO-Doped Alumina Fabricated by Spark Plasma Sintering

2010 ◽  
Vol 654-656 ◽  
pp. 2041-2044
Author(s):  
Byung Nam Kim ◽  
Keijiro Hiraga ◽  
Koji Morita ◽  
Hidehiro Yoshida
Keyword(s):  
Optical Properties ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Indirect Measure ◽  
Plasma Sintering ◽  
Spark Plasma

The microstructure and optical properties are investigated for MgO-doped alumina fabricated by spark plasma sintering at temperatures between 1100 and 1550 °C. The MgO doping renders the microstructure less sensitive to the sintering temperature by suppressing grain growth, whereas it has no significant effect on the densification of alumina and resultantly no effect in enhancing the total forward transmission. The value of the total forward transmission can be used as an indirect measure of the slight change in density.

Research on Two Sintered Techniques of Nanometer WC-Co Powder

2007 ◽  
Vol 534-536 ◽  
pp. 593-596 ◽  
Author(s):  
Lan Sun ◽  
Cheng Chang Jia ◽  
Hua Tang
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Grain Sizes ◽  
Sintering Time ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Hot Pressing Sintering

This paper concerned with SPS (spark plasma sintering), hot pressing of sinter nanometer WC-Co powder and discussed the density, hardness, microstructures and grain sizes of the alloys sintered by different styles. The results showed that SPS could lower the sintering temperature, increased the density and circumscribed the growth of grain size of WC. Hot pressing sintering could produce high density alloys and play well on the grain growth, but its sintering temperature and sintering time were larger than SPS. Besides, the hardness of the sintered cemented alloys that was dependent on the grain size and densification could also be improved by SPS and hot pressing.

Spark plasma sintering of Nd–Fe–B magnetic alloy

1999 ◽  
Vol 14 (6) ◽  
pp. 2540-2547 ◽  
Author(s):  
Z. G. Liu ◽  
M. Umemoto ◽  
S. Hirosawa ◽  
H. Kanekiyo
Keyword(s):  
Magnetic Properties ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Magnetic Alloy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Powder Particles ◽  
Lower Temperature

Spark plasma sintering was used to consolidate the crystallized Nd–Fe–B alloy powders. It was found that a higher sintering temperature can improve the consolidation significantly, whereas it deteriorates the magnetic properties drastically due to the appearance of a large amount of α–Fe phase and the grain growth. Sintering at lower temperature can preserve the magnetic properties better, while the powders cannot be consolidated into a fully dense compact, even under the higher pressure of 75 MPa. Finer starting powder particles show similar behavior.

Spark Plasma Sintering and Microstructural Characterization of Additive-Free Polycrystalline β-SiC

2009 ◽  
Vol 423 ◽  
pp. 67-72 ◽  
Author(s):  
A. Lara ◽  
R. Poyato ◽  
A. Muñoz ◽  
A.L. Ortiz ◽  
Arturo Domínguez-Rodríguez
Keyword(s):  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Microstructural Characterization ◽  
Holding Time ◽  
Plasma Sintering ◽  
Final Microstructure ◽  
Spark Plasma ◽  
Grain Growth Kinetics

Additive-free -SiC powders were sintered by means of Spark Plasma Sintering System. Experiments were performed in the temperature range from 1650°C to 2200°C, 3 to 10 min holding time and pressure from 50 until 150 MPa. In order to favour sinterization, the starting powder was mechanically activated: defect concentration was increased by centrifugal ball milling. Applied temperature, holding time and/or pressure were varied to analyze their effect on the densification and grain growth kinetics. The full sinterization of the material was obtained for temperatures as high as 1900°C and over. The relative density of the obtained material was high, up to 97.0  0.6 % the theoretical density for 2200°C sintering temperature. An intense grain growth took place while sintering. The final microstructure exhibited a grain size distribution range from 1.0 to 2.5 m, depending on the sintering conditions. Such grain growth strongly depends on the sintering time, not so much on the sintering temperature.

Effect of spark plasma sintering temperature on structure and phase composition of Ti-Al-Nb-based alloys

2017 ◽  
Vol 59 (11-12) ◽  
pp. 1033-1036 ◽  
Author(s):  
Sherzod Kurbanbekov ◽  
Mazhyn Skakov ◽  
Viktor Baklanov ◽  
Batyrzhan Karakozov
Keyword(s):  
Phase Composition ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Synthesis, microstructure, and properties of high purity Mo2TiAlC2 ceramics fabricated by spark plasma sintering

2020 ◽  
Vol 9 (6) ◽  
pp. 759-768
Author(s):  
Yunhui Niu ◽  
Shuai Fu ◽  
Kuibao Zhang ◽  
Bo Dai ◽  
Haibin Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
Layered Structure ◽  
High Purity ◽  
High Fracture Toughness ◽  
Temperature Range ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

AbstractThe synthesis, microstructure, and properties of high purity dense bulk Mo2TiAlC2 ceramics were studied. High purity Mo2TiAlC2 powder was synthesized at 1873 K starting from Mo, Ti, Al, and graphite powders with a molar ratio of 2:1:1.25:2. The synthesis mechanism of Mo2TiAlC2 was explored by analyzing the compositions of samples sintered at different temperatures. It was found that the Mo2TiAlC2 phase was formed from the reaction among Mo3Al2C, Mo2C, TiC, and C. Dense Mo2TiAlC2 bulk sample was prepared by spark plasma sintering (SPS) at 1673 K under a pressure of 40 MPa. The relative density of the dense sample was 98.3%. The mean grain size was 3.5 μm in length and 1.5 μm in width. The typical layered structure could be clearly observed. The electrical conductivity of Mo2TiAlC2 ceramic measured at the temperature range of 2–300 K decreased from 0.95 × 106 to 0.77 × 106 Ω–1·m–1. Thermal conductivity measured at the temperature range of 300–1273 K decreased from 8.0 to 6.4 W·(m·K)–1. The thermal expansion coefficient (TEC) of Mo2TiAlC2 measured at the temperature of 350–1100 K was calculated as 9.0 × 10–6 K–1. Additionally, the layered structure and fine grain size benefited for excellent mechanical properties of low intrinsic Vickers hardness of 5.2 GPa, high flexural strength of 407.9 MPa, high fracture toughness of 6.5 MPa·m1/2, and high compressive strength of 1079 MPa. Even at the indentation load of 300 N, the residual flexural strength could hold 84% of the value of undamaged one, indicating remarkable damage tolerance. Furthermore, it was confirmed that Mo2TiAlC2 ceramic had a good oxidation resistance below 1200 K in the air.

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