scholarly journals Influence of CFRC Insulating Plates on Spark Plasma Sintering Process

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 393
Author(s):  
Alexander M. Laptev ◽  
Jürgen Hennicke ◽  
Robert Ihl
Keyword(s):  
Temperature Distribution ◽  
Spark Plasma Sintering ◽  
Energy Demand ◽  
Composite Powders ◽  
Fem Method ◽  
Plasma Sintering ◽  
Axial Temperature ◽  
Spark Plasma ◽  
Power And Energy ◽  
The Impact

Spark Plasma Sintering (SPS) is a technology used for fast consolidation of metallic, ceramic, and composite powders. The upscaling of this technology requires a reduction in energy consumption and homogenization of temperature in compacts. The application of Carbon Fiber-Reinforced Carbon (CFRC) insulating plates between the sintering setup and the electrodes is frequently considered as a measure to attain these goals. However, the efficiency of such a practice remains largely unexplored so far. In the present paper, the impact of CFRC plates on required power, total sintering energy, and temperature distribution was investigated by experiments and by Finite Element Modeling (FEM). The study was performed at a temperature of 1000 °C with a graphite dummy mimicking an SPS setup. A rather moderate influence of CFRC plates on power and energy demand was found. Furthermore, the cooling stage becomes considerably longer. However, the application of CFRC plates leads to a significant reduction in the axial temperature gradient. The comparative analysis of experimental and modeling results showed the good capability of the FEM method for prediction of temperature distribution and required electric current. However, a discrepancy between measured and calculated voltage and power was found. This issue must be further investigated, considering the influence of AC harmonics in the DC field.

Effect of Spark Plasma Sintering on the Microstructure Evolution and Properties of M3:2 High-Speed Steel

2014 ◽  
Vol 788 ◽  
pp. 329-333
Author(s):  
Rui Zhou ◽  
Xiao Gang Diao ◽  
Jun Chen ◽  
Xiao Nan Du ◽  
Guo Ding Yuan ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Spark Plasma Sintering ◽  
High Speed ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Speed Steel ◽  
Continuous Heating ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

scholarly journals Mechanical Milling-Assisted Spark Plasma Sintering of Fine-Grained W-Ni-Mn Alloy

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1323 ◽  
Author(s):  
Yanlin Pan ◽  
Daoping Xiang ◽  
Ning Wang ◽  
Hui Li ◽  
Zhishuai Fan
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Interface Fracture ◽  
Composite Powders ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Binding Phase ◽  
Spark Plasma

Fine-grained W-6Ni-4Mn alloys were fabricated by spark plasma sintering (SPS) using mechanical milling W, Ni and Mn composite powders. The relative density of W-6Ni-4Mn alloy increases from 71.56% to 99.60% when it is sintered at a low temperature range of 1000–1200 °C for 3 min. The spark plasma sintering process of the alloy can be divided into three stages, which clarify the densification process of powder compacts. As the sintering temperature increases, the average W grain size increases but remains at less than 7 µm and the distribution of the binding phase is uniform. Transmission electron microscopy (TEM) observation reveals that the W-6Ni-4Mn alloy consists of the tungsten phase and the γ-(Ni, Mn, W) binding phase. As the sintering temperature increases, the Rockwell hardness and bending strength of alloys initially increases and then decreases. The optimum comprehensive hardness and bending strength of the alloy are obtained at 1150 °C. The main fracture mode of the alloys is W/W interface fracture.

Enhancing Mechanical Properties of Various Sintered Pellets with Nano-Additives

2021 ◽  
Vol 410 ◽  
pp. 62-67
Author(s):  
Tien Hiep Nguyen ◽  
Yury V. Konyukhov ◽  
Van Minh Nguyen
Keyword(s):  
Mechanical Properties ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Size Range ◽  
Pressureless Sintering ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Nano Additives ◽  
Free Spaces ◽  
The Impact

The impact of Fe, Co, Ni nano-additives on the density, microhardness and bending strength was investigated for several sintered pellets. Fe, Co, Ni nanopowders (NP) were prepared in the size range 67-94 nm using chemical metallurgy techniques. These powders (0.5 wt. %) were dispersed into three sets of micron powders: Co (+0.5 wt. % Co NP); Fe (+0.5 wt. % Fe NP); Fe+0.5wt. % C (+0.5 wt. % Co and 0.5 wt. % Ni NP). Mixtures were further mixed and processed using a magnetic mill and a turbulent mixer. Sintering was carried out using spark plasma sintering (SPS) as well as pressureless sintering (PS). The densities of sintered pellets were found to increase by 2.5-3% (SPS) and 3-5% (PS) in the presence of nano-additives; corresponding increases in microhardness and bending strength were determined to be 7.9-11.1% and 17.9-38.7%, respectively. These results are discussed in terms enhanced packing due to interparticle sliding and the filling of free spaces with the nanodisperse phase.

Characteristic and Sinterability of Alumina-Zirconia-Yttria Nanoparticles Prepared by Different Chemical Methods

2014 ◽  
Vol 87 ◽  
pp. 30-35
Author(s):  
Janis Grabis ◽  
Dzidra Jankovica ◽  
Ints Steins ◽  
Krisjanis Smits ◽  
Inta Sipola
Keyword(s):  
Phase Transition ◽  
Spark Plasma Sintering ◽  
Molten Salts ◽  
Preparation Method ◽  
Bulk Materials ◽  
Chemical Methods ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact ◽  
Sintering Method

The characteristics and sinterability of the Al2O3-ZrO2(Y2O3) nanoparticles produced by simple and effective microwave and molten salts methods and processed by using spark plasma sintering were studied and compared. The crystalline powders with the specific surface area in the range of 72–108 m2/g and crystallite size of 5–13 nm were obtained by calcination of samples prepared by both methods at 800 °C. The content of t-ZrO2 phase depends on concentration of Al2O3, Y2O3 and on calcination temperature but the impact of the preparation method is insignificant. The phase transition of tetragonal ZrO2 to monoclinic for the samples without Y2O3 started at 1000 °C though it was incomplete in the case of high content of Al2O3. The bulk materials with relative density of 86.1–98.7% were fabricated by the spark plasma sintering method at 1500–1600 °C depending on the content of Al2O3 and Y2O3.

scholarly journals Spark Plasma Sintering Behavior of Nb-Mo-Si Alloy Powders Fabricated by Hydrogenation-Dehydrogenation Method

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3549 ◽  
Author(s):  
Sung Lee ◽  
Ki Park ◽  
Jang-Won Kang ◽  
Yanghoo Kim ◽  
Hyun-Su Kang ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Powder Metallurgy Method ◽  
Composite Powders ◽  
Plasma Sintering ◽  
Formation Behavior ◽  
Spark Plasma ◽  
Two Phases ◽  
Nb5si3 Phase

In this study, the sintering behaviors of Nb-6Mo-20Si-3Cr (at percentage) in situ composite powders were studied. The Nb alloy powder was fabricated by a hydrogenation-dehydrogenation method, and both the alloy ingot and powders consisted of two phases: An Nb metal phase and the α-Nb5Si3 phase. Consolidation of the alloy powders was performed at 1500, 1600, and 1700 °C using spark plasma sintering, and the microstructures and phases formed at various sintering temperatures were analyzed. Micropores were observed in the compact sintered at 1500 °C due to the lack of complete densification at that temperature. The densification was completed at 1600 °C and the microstructure was slightly coarsened at 1700 °C compared to the microstructure of the compact sintered at 1600 °C. The microstructures prepared by the powder metallurgy method were finer than the microstructure of the ingot prepared by the casting method. The phase formation behavior varied according to the sintering temperature. Specifically, the α-Nb5Si3 phase, which is a stable structure of the Nb5Si3 phase at a low temperature, was transformed to the β-Nb5Si3 phase (which is stable at a high temperature) with an increasing sintering temperature.

scholarly journals Calculation of the Temperature Distribution in Cylindrical Samples of Alumina and Copper Produced by Spark Plasma Sintering

Ceramics ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 437-446
Author(s):  
Vyacheslav V. Krizhanovskiy ◽  
Vyacheslav I. Mali
Keyword(s):  
Electrical Conductivity ◽  
Temperature Distribution ◽  
Aluminum Oxide ◽  
Physicochemical Properties ◽  
Spark Plasma Sintering ◽  
Numerical Calculations ◽  
Heating Rates ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Cylindrical Samples

Numerical calculations were carried out to simulate, under conditions of close spark plasma sintering (SPS), the temperature distribution during the passage of current in dense cylindrical samples of two materials: aluminum oxide and copper located in graphite forms and clamped between cylindrical graphite punches. The investigated materials differ greatly in their electrical conductivity and other physicochemical properties. Calculations were carried out for various geometric parameters of the samples, as well as graphite molds and punches at varying heating rates from the passing current.

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