Physico-chemical and mechanical properties of Ti3SiC2-based materials elaborated from SiC/Ti by reactive spark plasma sintering (original) (raw)
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Ti 3 SiC 2 was elaborated by two different methods: (i) Spark plasma sintering of 5Ti/2SiC/C powders and (ii) mechanical alloying of powders followed by Spark plasma sintering. The results showed that mechanical alloying was not advantageous for pure Ti 3 SiC 2 formation but it can significantly improve the density of the obtained bulk material via the particles refinement as well as the microhardness by increasing the TiC content. It was found that the relative density was increased up to 98.58% for the sintered mechanically alloyed sample whereas it was not more than 96.04% for the sintered 5Ti/2SiC/C starting powders. The Vickers microhardness measured for both bulk samples demonstrates a high improvement for the previously mechanically alloyed powder mixture, as it was of about 1282 Hv and only 581.2 Hv for the alloy obtained from 5Ti/2SiC/C starting powders.
The effect of preceding mechanical alloying on titanium silicon carbide (Ti 3 SiC 2 ) formation from a powder mixture of 5Ti/2Si/3C through spark plasma sintering technique as well as the mechanical property of the bulk material was investigated in this paper. The results showed that mechanical alloying can significantly improve the density of the obtained bulk material via the particles refinement as well as the microhardness by increasing the TiC content. The corresponding relative density of the spark plasma sintered samples from elemental powders of Ti/Si/C and the previously mechanically alloyed ones were calculated to be respectively 93.20% and 99.82%. The measured microhardness values of the different samples were respectively about 462 and 955 Hv.
Low temperature synthesis of high-purity Ti3SiC2 via additional Si through spark plasma sintering
Journal of Alloys and Compounds, 2019
To reveal the efficacy of Si amount on the high-purity Ti 3 SiC 2 synthesis, starting powders of Ti:Si:TiC:Al = 1:(1+x):2:0.2 with various Si amounts (x = 0.1, 0.2 and 0.3) were sintered through SPS. The sintering process was conducted at 1100-1250 o C for 8 min under pressure of 40 MPa. Undesirable TiC impurity initiated to form at temperatures above 1200 o C and left the primary phase near 1250 o C from the Ti:Si:TiC:Al = 1:1.3:2:0.2. It was found that Si content had a key role in the improvement of Ti 3 SiC 2 purity. The outcomes demonstrated that high-purity Ti 3 SiC 2 could be acquired though the Ti:Si:TiC:Al = 1:1.2:2:0.2 at 1150 o C. The Young's modulus of Ti 3 SiC 2 sample was 346 GPa and decreased with increasing impurity phases.
Journal of Alloys and Compounds, 2017
This paper reports on Ti 3 SiC 2 formation, from 2Si/3TiC starting powders, using spark plasma sintering as a reactive process within the temperature range of 1250-1400°C and for different holding times. The microstructure and mechanical properties of the bulk materials were studied as a function of temperature and holding time under a constant pressure of 60 MPa. The highest Ti 3 SiC 2 conversion (87 wt%) was achieved for a temperature of 1400°C during 20 min. At these optimum conditions, the relative density was higher than 99%. The Young's modulus, the Vickers hardness and the compressive yield strength of the corresponding sample were: 325 GPa, 4.9 GPa and 995 MPa, respectively.
Silicon, 2021
Fully-dense Ti 3 SiC 2-SiC composites were in-situ synthesized and sintered through a reactive hot-pressing process using TiC and Si powders with different molar ratios of 3TiC:3Si, 3TiC:2Si (stoichiometric composition), and 3TiC:1.5Si. Phase characterization of the hot-pressed specimens was performed by X-ray diffraction (XRD) analysis, and the microstructures were studied by scanning electron microscope (SEM). The mechanical properties of the hot-pressed composites were investigated in terms of Vickers hardness, fracture toughness, and flexural strength. It was found that the in-situ synthesized SiC particles, with platelet morphology, have been distributed in the in-situ formed Ti 3 SiC 2 matrix. The highest Vickers hardness belonged to the 3TiC:1.5Si sample with a value of 14.2 GPa, related to the presence of SiC and residual TiC phase in the microstructure. The flexural strength enhanced with increasing the molar value of Si, due to the presence of the free Si phase in the sample and the further formation of the SiC phase. The 3TiC:3Si sample achieved the highest fracture toughness of 10.1 MPa.m 1/2 and the highest flexural strength of 576 MPa.
Spark plasma sintering of TiC–SiCw ceramics
Ceramics International, 2019
Silicon carbide whiskers (SiC w) in TiC had impressive impacts on the properties and made it possible for special applications which generally would not be conceivable with TiC alone. In the present work, SiC w reinforced TiC based composites were prepared by spark plasma sintering (SPS) technique, at the temperature of 1900°C under the pressure of 40 MPa for sintering time of 7 min. To test out the effects of different amount of SiC whisker (0, 10, 20 and 30 vol%) on the characteristics of TiC, the sintered samples were investigated about sinterability and physical-mechanical properties. Microstructure observations and density measurements confirmed that the composites were dense with uniformly distributed reinforcement, and the specimen doped with higher than 10 vol% SiC w could attain higher relative density (> 100%) than pure TiC and TiC-10 vol% SiC w. Also, the highest values for hardness (29.04 GPa) and thermal conductivity (39.2 W/mK) were achieved in specimen containing 30 vol% SiC w , whereas the optimum bending strength (644 MPa) was recorded in material containing 20 vol% SiC w. It seems that one of the reasons which contributes to this trend of properties variation is the generation of near-stoichiometric TiC x phase and new Ti 3 SiC 2 compound.
Synthesis of Ti3SiC2 by Reaction of TiC and Si Powders
Ceramic Engineering and Science Proceedings, 2009
The MAX phase Ti 3 SiC 2 has been synthesized from starting powder mixtures which do not include pure titanium. The presence of pure titanium in a powder is problematic because of its oxidizing, and in the form of a finely divided powder, explosive nature. The aim of this study was to evaluate the synthesis of bulk polycrystalline samples of Ti 3 SiC 2 from a starting powder mixture which is more suited for large scale production. Titanium silicon carbide MAX phase was synthesized by pressureless sintering of ball milled TiC and Si powders of six different compositions. The sintering reactions were evaluated in situ by dilatometer analysis under flowing argon gas. The as-sintered samples were evaluated using mainly x-ray diffraction (XRD) analysis. This study showed that titanium carbide, silicon carbide and titanium disilicide were present as intermediate or secondary phases in the samples. Our results indicate that TiSi 2 is an intermediate phase to the formation of Ti 3 SiC 2 when excess Si is present. The excess of silicon also proved beneficial for the synthesis of the MAX phase and there is a Si content which is optimal with respect to the maximum MAX phase content of the final product. The Ti 3 SiC 2 was found to decompose into TiC and gaseous Si at high temperatures.
Processing and Characterization of Spark Plasma Sintered SiC-TiB2-TiC Powders
Materials, 2022
SiC-TiB2-TiC composites with matrices consisting of semiconductor material (SiC), conductive materials (TiB2-TiC), or their combination were fabricated by spark plasma sintering (SPS) at 2000 °C in a vacuum under a pressure of 80 MPa for 3 min. The composition and microstructure of the obtained composites were studied by X-ray diffraction and a scanning electron microscope equipped with an energy-dispersive detector. The flexural strength, Vickers hardness, and fracture toughness of SPSed samples were determined. Based on the observations in this work, three variations of the sintering process were proposed with different matrix compositions. The dense (99.7%) 60SiC-25TiB2-15TiC vol.% sintered ceramic composites exhibited the highest strength and hardness values of the studied composites, as well as a fracture toughness of 6.2 MPa·m1/2.
Synthesis of Ti3SiC2 by high energy ball milling and reactive sintering from Ti, Si, and C elements
Journal of Nuclear Materials, 2009
We present an original method of preparation of nanostructured Ti 3 SiC 2 compound based on high energy ball milling and reactive sintering techniques. Starting materials are Ti, Si, and C elements. X-ray diffraction and secondary electron microscopy are used to identify the formed phases and to analyze the obtained microstructures. Lower milling intensity and shorter milling time are found as the best milling conditions in order to get an intimate mixture of the three elements without formation of detectable secondary phases. The optimized sintering temperature is equal to 1350°C. A method used for minimizing the oxygen content in the final compound is presented.
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2010
Binary phase TiC/Ti3SiC2 composites have been synthesized by reactive hot-pressed sintering (HPS) with the aim of developing a new hard product. Raw powders of TiC, Ti and Si with compositions 2TiC/1Ti/1Si (2:1:1) and 2TiC/1Ti/1.1Si (2:1:1.1) have been used as the starting materials for the synthesis. The phase content and microstructure of synthesized composites have been analyzed using X-ray diffractometer (XRD) and scanning electron microscope (SEM). The mechanical properties such as four-point flexural strength and fracture toughness have been investigated for different processing parameters. The phase content (Ti3SiC2:TiC) of the composite synthesized from (2:1:1) powder vary from (81:19) to (71:29) with the hot pressing temperature increased from 1500 to 1700 °C. This sample exhibits maximum flexural strength of 627 MPa and fracture toughness of 6.84 MPa m1/2. The maximum apparent density is found to be 4.65 g/cm3 for this sample at optimum hot pressing temperature of 1500 °C. The composite synthesized from (2:1:1.1) composition shows improvement in the mechanical properties compared to 2:1:1 composition. The relationship between the phase content and mechanical properties has been investigated.