scholarly journals Density, Microstructure, Strength and Fractography of Spark Plasma and Conventionally Sintered Mn Steels

2017 ◽  
Vol 17 (2) ◽  
pp. 93-103
Author(s):  
M. Tenerowicz-Zaba ◽  
M. Kupkova ◽  
M. Kabatova ◽  
E. Dudrova ◽  
M. Dzupon ◽  
...  

Abstract The aim of the study was to investigate Spark Plasma Sintering (SPS) of 1-3%Mn steels and compare the resultant microstructures, strengths and failure mechanisms with those of conventionally sintered materials. SPS was performed in a vacuum of 5 Pa at 1000°C for 15min under a uniaxial pressure of 20 MPa. The heating rate of 100°C/min was applied. For conventional processing, mixtures of powders were prepared in a Turbula mixer for 30 minutes. Samples were single pressed at 660 MPa, according to PN-EN ISO 2740 standard. Sintering of compacts was carried out in a laboratory tube furnace at 1120°C and 1250°C for 60 minutes in a mixture of 95%N2-5%H2. Heating and cooling rates were 75C°/min and 60°C/min, respectively. The density of SPS samples was higher (up to 7.37 g/cm3) than those after conventional sintering (up to 6.7 g/cm3). Yield strengths of SPS samples were in the range 920-1220 MPa, compared to the maximum of 602 MPa for conventionally sintered Fe-3%Mn-0.8%C. Transverse rupture strengths were the same for this alloy, 1234 MPa, but reached 1473 MPa for SPS 2Mn variant. Interfaces in SPS samples were significantly less contaminated with oxides, which is the result of a more favorable microclimate and pressure acting during SPS. These preliminary results indicate that further research on the SPS of Mn steels is warranted.

2008 ◽  
Vol 368-372 ◽  
pp. 601-603
Author(s):  
Xi Wei Qi ◽  
Ji Zhou ◽  
Zhen Xing Yue ◽  
Ming Ya Li ◽  
Xiu Mei Han

Dense NiCuZn ferrites consisting of fine grains were prepared by spark plasma sintering (SPS) at 750°C for 3 min under a uniaxial pressure of 15 MPa. The powders were densified to >95% of theoretical density by the SPS process, and the average grain size of the prepared NiCuZn ferrite was < 1 /m. The saturation magnetization of prepared specimens (without further annealing treatment) was approximate 50.54 emu/g, which was slightly smaller than that of 52.21 emu/g for specimens prepared by conventional sintering at 980°C for 4 h. Phase identifications indicated that prepared NiCuZn ferrite existed impurity phase (Cu2O), and Cu2O would gradually transform to CuO when annealing temperature increased.


2006 ◽  
Vol 49 ◽  
pp. 45-50 ◽  
Author(s):  
Christophe Drouet ◽  
C. Largeot ◽  
G. Raimbeaux ◽  
Claude Estournès ◽  
Gérard Dechambre ◽  
...  

Calcium phosphates (Ca-P) are major constituents of calcified tissues, and are also extensively used for the elaboration of biomaterials. However, the usual high-temperature sintering processes generally lead to strong alterations of their chemical, physical and biological properties. Spark plasma sintering (SPS) is a non-conventional sintering technique based on the use of pulsed current, enabling fast heating and cooling rates, and lower sintering temperatures are often observed. The sintering of several orthophosphates (DCPD, amorphous TCP, beta-TCP, OCP, HA and biomimetic nanocrystalline apatites) by SPS was investigated in order to track potential advantages of this technique over usual Ca-P sintering methods. Special attention was given to the SPS consolidation of highly bioactive nanocrystalline apatites.


2018 ◽  
Vol 224 ◽  
pp. 01055 ◽  
Author(s):  
Yuri Pristinskiy ◽  
Nestor Washington Solis Pinargote ◽  
Anton Smirnov

Spark plasma sintering (SPS) is an extremely fast solidification technique for compounds that are difficult to sinter within the material group metals, ceramics or composites. SPS uses a uniaxial pressure and a very rapid heating cycle to consolidate these materials. This direct way of heating allows the application of very high heating and cooling rates, enhancing densification over grain growth promoting diffusion mechanisms allowing maintaining the intrinsic properties of nanopowders in their fully dense products. The ZrO2-TiN cermets prepared by SPS processing achieves the enhanced mechanical properties with the hardness of 15.1 GPa and the fracture toughness of 9.1 MPa∙m1/2 in comparison to standard reference ZrO2-TiN material.


2012 ◽  
Vol 508 ◽  
pp. 32-37
Author(s):  
Lian Meng Zhang ◽  
Qi Long Guo ◽  
Jun Guo Li ◽  
Qiang Shen

The Nearly Full Dense Zr2Al3C4 Ceramic Was Successfully Fabricated at 1800 °C for 10 min under a Uniaxial Load of 20 MPa in Vacuum by the Spark Plasma Sintering Process, Using a Mixture of Zr, Al and Graphite Powders as Raw Materials. The Reaction Route of Synthesis as Well as the Sintering Conditions of the SPS Technique Were Discussed Based on X-Ray Diffraction Results. The Results Showed that the Heating Rate Can Largely Affect the Loss and Aggregation of Molten Al. Moreover, the Contents of Al4O4C and the Elevated Sintering Temperature Were Beneficial for the Synthesis of Zr2Al3C4 Ceramic. The Microstructures of the Samples Were Observed by Scanning Electron Microscopy, Showing that the as-Synthesized Zr2Al3C4 Has an Anisotropic Microstructure Consisting of Elongated Grains. Compared to the Hot-Pressing, the Starting Temperature for the Formation of Zr3Al3C5 and Al4O4C Phases Was Rather Low. It Indicates that the SPS Technique Can Rapidly Synthesize Zr2Al3C4 from the Zr/Al/C Powders in a Relatively Low Temperature Range. The Mechanical Properties of the Sintered Materials Were Also Investigated, Including the Hardness of 11.66±0.34 GPa, and Fracture Toughness of 4.0 ± 0.4 MPa×m1/2.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 141
Author(s):  
Kirill V. Kuskov ◽  
Mohammad Abedi ◽  
Dmitry O. Moskovskikh ◽  
Illia Serhiienko ◽  
Alexander S. Mukasyan

Spark plasma sintering (SPS) is widely used for the consolidation of different materials. Copper-based pseudo alloys have found a variety of applications including as electrodes in vacuum interrupters of high-voltage electric circuits. How does the kinetics of SPS consolidation for such alloys depend on the heating rate? Do SPS kinetics depend on the microstructure of the media to be sintered? These questions were addressed by the investigation of SPS kinetics in the heating rate range of 0.1 to 50 K/s. The latter conditions were achieved through flash spark plasma sintering (FSPS). We also compared the sintering kinetics for the conventional copper–chromium mixture and for the mechanically induced copper/chromium nanostructured particles. It was shown that, under FSPS conditions, the observed maximum consolidation rates were 20–30 times higher than that for conventional SPS with a heating rate of 100 K/min. Under the investigated conditions, the sintering rate for mechanically induced composite Cu/Cr particles was 2–4 times higher compared to the conventional Cu + Cr mixtures. The apparent sintering activation energy for the Cu/Cr powder was twice less than that for Cu–Cr mixture. It was concluded that the FSPS of nanostructured powders is an efficient approach for the fabrication of pseudo-alloys.


Author(s):  
B Stalin ◽  
M Ravichandran ◽  
M Balasubramanian ◽  
C Anand Chairman ◽  
D Pritima ◽  
...  

Author(s):  
Akeem Yusuf Adesina ◽  
Muzafar Hussain ◽  
Abbas Saeed Hakeem ◽  
Abdul Samad Mohammed ◽  
Muhammad Ali Ehsan ◽  
...  

Author(s):  
Yingchun Shan ◽  
Xialu Wei ◽  
Xiannian Sun ◽  
Elisa Torresani ◽  
Eugene A. Olevsky ◽  
...  

2005 ◽  
Vol 287 ◽  
pp. 335-339 ◽  
Author(s):  
Kyeong Sik Cho ◽  
Kwang Soon Lee

Rapid densification of the SiC-10, 20, 30, 40wt% TiC powder with Al, B and C additives was carried out by spark plasma sintering (SPS). In the present SPS process, the heating rate and applied pressure were kept at 100°C/min and at 40 MPa, while the sintering temperature varied from 1600-1800°C in an argon atmosphere. The full density of SiC-TiC composites was achieved at a temperature above 1800°C by spark plasma sintering. The 3C phase of SiC in the composites was transformed to 6H and 4H by increasing the process temperature and the TiC content. By tailoring the microstructure of the spark-plasma-sintered SiC-TiC composites, their toughness could be maintained without a notable reduction in strength. The strength of 720 MPa and the fracture toughness of 6.3 MPa·m1/2 were obtained in the SiC-40wt% TiC composite prepared at 1800°C for 20 min.


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