Fine-Grained W-Ni-Fe Heavy Alloys Prepared by Spark Plasma Sintering

2016 ◽  
Vol 849 ◽  
pp. 745-752 ◽  
Author(s):  
Yan Jiao Wu ◽  
Yun Kai Li ◽  
Dong Hui Yu
Keyword(s):  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Dynamic Compression ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Heavy Alloys ◽  
Close Relationship ◽  
Static Tensile ◽  
Spark Plasma

Fine-grained W-Ni-Fe heavy alloys (WHAs) with grain size of about 1-3μm were obtained by Spark Plasma Sintering (SPS) process. The composition of the alloy is consisted of 65 to 75 wt % W, with a Ni/Fe ratio ranging from zero to 7/3. In the lower sintering temperature range of 1100-1300°C, the WHAs showed the highest relative density of 98.6%, and when the sintering temperature was 1250 °C, the relative density of the WHAs prepared by the same techniques increased by decreasing of the content of W. Meanwhile the relative density of the alloy also increased with an increase of Ni /Fe ratio. The results show that the static tensile properties of the WHAs have a close relationship with the ratio of Ni / Fe. The tensile strength and the ductility of the sample W70-Ni21-Fe9 was 890 MPa and 3%. Furthermore, the dynamic compression strength of W70-Ni21-Fe9 was 1744 MPa.

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.

scholarly journals Characterization of Multiwalled Carbon Nanotube-Reinforced Hydroxyapatite Composites Consolidated by Spark Plasma Sintering

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Duk-Yeon Kim ◽  
Young-Hwan Han ◽  
Jun Hee Lee ◽  
Inn-Kyu Kang ◽  
Byung-Koog Jang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Pull Out ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Mwnt Content

Pure HA and 1, 3, 5, and 10 vol% multiwalled carbon nanotube- (MWNT-) reinforced hydroxyapatite (HA) were consolidated using a spark plasma sintering (SPS) technique. The relative density of pure HA increased with increasing sintering temperature, but that of the MWNT/HA composite reached almost full density at 900°C, and then decreased with further increases in sintering temperature. The relative density of the MWNT/HA composites increased with increasing MWNT content due to the excellent thermal conductivity of MWNTs. The grain size of MWNT/HA composites decreased with increasing MWNT content and increased with increasing sintering temperature. Pull-out toughening of the MWNTs of the MWNT/HA composites was observed in the fractured surface, which can be used to predict the improvement of the mechanical properties. On the other hand, the existence of undispersed or agglomerate MWNTs in the MWNT/HA composites accompanied large pores. The formation of large pores increased with increasing sintering temperature and MWNT content. The addition of MWNT in HA increased the hardness and fracture toughness by approximately 3~4 times, despite the presence of large pores produced by un-dispersed MWNTs. This provides strong evidence as to why the MWNTs are good candidates as reinforcements for strengthening the ceramic matrix. The MWNT/HA composites did not decompose during SPS sintering. The MWNT-reinforced HA composites were non-toxic and showed a good cell affinity and morphologyin vitrofor 1 day.

Effects of Processing Parameters of SPS on the Densification and Texture of LaPO4 Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1059-1061 ◽  
Author(s):  
Ai Bing Du ◽  
Zhi Xue Qu ◽  
Chun Lei Wan ◽  
Ruo Bing Han ◽  
Wei Pan
Keyword(s):  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Preferred Orientation ◽  
Holding Time ◽  
Plasma Sintering ◽  
Spark Plasma

Spark plasma sintering was used to fabricate the LaPO4 ceramics and the effect of SPS holding time and sintering temperature on the densification and texture of LaPO4 ceramics were studied. The results revealed that holding time had no obvious influence on the densification of LaPO4 ceramics under the present process. The density increases with the increase of sintering temperature, when it reached 1350°C, the relative density kept nearly constant of 98.6 %. The preferred orientation of LaPO4 ceramics approximately increases with the increase of sintering temperature, but contrary impact in holding time.

Spark Plasma Sintering TiAl Alloy from Mechanically Activated Powders

2011 ◽  
Vol 250-253 ◽  
pp. 3309-3312 ◽  
Author(s):  
Zhi Wei Wang ◽  
Hong Cheng ◽  
Hui Ming Cheng
Keyword(s):  
Spark Plasma Sintering ◽  
Tial Alloy ◽  
Sintering Temperature ◽  
Al Alloy ◽  
Tial Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Short Period ◽  
Spark Plasma ◽  
Higher Temperature

Powder of Ti-46at%Al alloy was synthesized through mechanical activation (MA) and then sintered and concurrently consolidated in a short sintering time of 900 s by using spark plasma sintering (SPS) process. The XRD and SEM profiles show that the microstructures of TiAl alloys contained γ TiAl and small amount α-2 Ti3Al phase, whose amount can be controlled by the sintering temperature. The compacts retained the original fine-grained fully densified bodies by avoiding an excessively high sintering temperature. The alloys sintered at higher temperature with this process showed a coarser microstructure. So it is possible to produce dense nanostructured TiAl alloys by mechanically activated spark plasma sintering (MASPS) within a very short period of time.

TiAl Alloy Spark Plasma Sintered from Mechanically Activated Powders

2011 ◽  
Vol 284-286 ◽  
pp. 2336-2339
Author(s):  
Zhi Wei Wang ◽  
Jun Chen
Keyword(s):  
Spark Plasma Sintering ◽  
Tial Alloy ◽  
Sintering Temperature ◽  
Al Alloy ◽  
Tial Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Short Period ◽  
Spark Plasma ◽  
Higher Temperature

Powder of Ti-46at%Al alloy was synthesized through mechanical activation (MA) and then sintered and concurrently consolidated in a short sintering time of 900 s by using spark plasma sintering (SPS) process. The XRD and SEM profiles show that the microstructures of TiAl alloys contained γ TiAl and small amount α-2 Ti3Al phase, whose amount can be controlled by the sintering temperature. The compacts retained the original fine-grained fully densified bodies by avoiding an excessively high sintering temperature. The alloys sintered at higher temperature with this process showed a coarser microstructure. So it is possible to produce dense nanostructured TiAl alloys by mechanically activated spark plasma sintering (MASPS) within a very short period of time.

Spark Plasma Sintering and Characterization of WC-Co-cBN Composites

2014 ◽  
Vol 616 ◽  
pp. 194-198 ◽  
Author(s):  
Jian Feng Zhang ◽  
Rong Tu ◽  
Takashi Goto
Keyword(s):  
Fracture Toughness ◽  
Phase Transformation ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Moderate Pressure ◽  
Plasma Sintering ◽  
Spark Plasma

WC-Co-cBN composites were consolidated by SPS at 1373 to 1673 K under a moderate pressure of 100 MPa. The addition of cBN increased the starting and finishing temperature of shrinkage and decreased the relative density of WC-Co. The relative density of WC-(10-20 vol%) cBN composites was about 97-100% at 1573 K and decreased with increasing the sintering temperature to 1673 K due to the phase transformation of cBN to hBN. The highest hardness and fracture toughness of WC-Co-20 vol% cBN composite sintered at 1573 K were 23.2 GPa and 8.0 MP m1/2, respectively.

Fabrication of Dense Nanostructured Bulk Ceramics by Means of Spark-Plasma-Sintering (SPS) Processing

2016 ◽  
Vol 838-839 ◽  
pp. 225-230 ◽  
Author(s):  
Koji Morita ◽  
Byung Nam Kim ◽  
Hidehiro Yoshida ◽  
Keijiro Hiraga ◽  
Yoshio Sakka
Keyword(s):  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
High Heating Rate ◽  
Fine Grained ◽  
Fine Grain ◽  
Plasma Sintering ◽  
High Heating ◽  
Spark Plasma ◽  
Primary Advantage

In order to fabricate fine-grained and dense nanoceramic materials, the effect of spark-plasma-sintering (SPS) conditions was examined in MgAl2O4 spinel as a reference material. The SPS conditions, such as heating rate and loading temperature, strongly affected the microstructures. Although the density can be improved with decreasing the heating rate to less than 10 °C/min, it requires a long processing time. In order to fully utilize the high heating rate that is a primary advantage of the SPS technique, load controlling is very effective to achieve high density with maintaining fine grain size. An increase in the loading temperature during SPS processing can reduce the residual porosity in a spinel even at the widely used high heating rate of 100 °C/min. This suggests that for the SPS processing in ceramics, the load controlling is an important factor as well as the heating rate and sintering temperature.

Spark Plasma Sintering of α-Si3N4 Ceramics with MgO-Al2O3 as Sintering Additives

2007 ◽  
Vol 351 ◽  
pp. 176-179 ◽  
Author(s):  
Fa Qiang Yan ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Relative Density ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Close Correlation ◽  
Liquid Phase Sintering ◽  
Sintering Additives ◽  
Sintering Mechanism ◽  
Plasma Sintering ◽  
Spark Plasma

In the present study, α-Si3N4 is prepared by using MgO and Al2O3 as the sintering additives and spark plasma sintering (SPS) technique. The SPS sintering mechanism is discussed. The relationship between the content of sintering additives, sintering temperature and relative densities of the samples is analyzed. The results suggest that when the sintering temperature is 1300-1500°C, the content of sintering additives is 6wt.%-10wt.%, the relative density of sintered samples is 64%-96%. When the sintering temperature reaches 1400°C, the content of sintering additives is 10%, the samples can be fully dense sintered and the relative density can be up to 95%. The sintering mechanism is liquid phase sintering. The bending strength of the sintered samples is 50-403MPa and has a close correlation with the relative density.

scholarly journals Effect of High Pressure Spark Plasma Sintering on the Densification of a Nb-Doped TiO2 Nanopowder

Ceramics ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 507-520
Author(s):  
Alexandre Verchère ◽  
Sandrine Cottrino ◽  
Gilbert Fantozzi ◽  
Shashank Mishra ◽  
Thomas Gaudisson ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Sintering Process ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Lower Temperature

Sintering under pressure by means of the spark plasma sintering (SPS) technique is a common route to reduce the sintering temperature and to achieve ceramics with a fine-grained microstructure. In this work, high-density bulk TiO2 was sintered by high pressure SPS. It is shown that by applying high pressure during the SPS process (76 to 400 MPa), densification and phase transition start at lower temperature and are accelerated. Thus, it is possible to dissociate the two densification steps (anatase then rutile) and the transition phase during the sintering cycle. Regardless of the applied pressure, grain growth occurs during the final stage of the sintering process. However, twinning of the grains induced by the phase transition is enhanced under high pressure resulting in a reduction in the crystallite size.

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