Manufacturing of high volume fraction of nanolayered Ti3AlC2 metallic ceramics (original) (raw)
Related papers
Ceramic Engineering and Science Proceedings, 2015
The paper discusses the development of a new material system for interconnect application in Solid Oxide Fuel Cells (SOFC) based on TiC-Ti 3 Al. Nano-sized TiC powders utilized in this research were synthesized using carbon coated TiO 2 precursors from a patented process. The pressureless sintering of TiC-Ti 3 Al in a vacuum was applied at temperatures between 1100°C and 1500°C and content of Ti 3 Al was varied in the range of 10-40 wt%. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used for phase evaluation and sintering behavior. Relative density increased markedly with increasing sintering temperature because of grain growth and formation of the Ti 3 AlC 2 secondary phase. Dense products (495% TD) were prepared from nanosized TiC powders with 10 and 20 wt% Ti 3 Al, but with about 8 to 10% porosity for 30 and 40 wt% Ti 3 Al. The mechanical properties were determined from Vickers hardness and fracture toughness calculations. Vickers hardness decreased and fracture toughness increased with increasing Ti 3 Al content. The electrical conductivity and oxidation behavior of TiC-Ti 3 Al composites were investigated to evaluate the feasibility for SOFC interconnect application. The electrical conductivity measurements in the air at 800°C for 100 h were made using the Kelvin 4-wire method.
Journal of the Ceramic Society of Japan, 2013
Textured, dense, polycrystalline Ti 3 AlC 2 ceramics was fabricated by spark plasma sintering (SPS) of plate-like Ti 3 AlC 2 powder synthesized by a reactive SPS-heat treatment of elemental Ti, Al and carbon black powders. The relative density was found to exceed 99% for samples sintered at 1573 K. The Lotgering orientation factor was determined to be f(00l) = 0.69. The crack propagation behavior near the indentation marks formed by a force of 49 N was observed. On the surface parallel to the SPSloading direction, the toughening mechanism of crack deflection was observed.
International Journal of Mechanical and Production Engineering Research and Development, 2020
Aluminium matrix infused with titanium carbide (TiC) particles was prepared by means of powder metallurgy process. The effect of TiC addition on microstructure, hardness and electrical conductivity of as-sintered Al-TiC with 2 µm and ≤ 200 nm reinforcement were investigated. Microstructure studies reveal the even distribution of TiC particles in the aluminium matrix. With increasing addition of TiC, the hardness of composites increased after the 10% and suddenly reduced because the composites reduce its resistance and create more sites for crack initiation. Hardness and electrical conductivity of composites have been varied based on particle size variation of TiC.
Ceramics International, 2016
The paper discusses the development of a new material system for interconnect application in Solid Oxide Fuel Cells (SOFC) based on TiC-Ti 3 Al. Nano-sized TiC powders utilized in this research were synthesized using carbon coated TiO 2 precursors from a patented process. The pressureless sintering of TiC-Ti 3 Al in a vacuum was applied at temperatures between 1100-1500 o C and content of Ti 3 Al was varied in the range of 10-40 wt. %. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used for phase evaluation and sintering behavior. Relative density increased markedly with increasing sintering temperature because of grain growth and formation of the Ti 3 AlC 2 secondary phase. Dense products (>95% TD) were prepared from nanosized TiC powders with 10 and 20 wt. % Ti 3 Al, but with about 8 to 10% porosity for 30 and 40 wt. % Ti 3 Al. The mechanical properties were determined from Vickers hardness and fracture toughness calculations. Vickers hardness decreased and fracture toughness increased with increasing Ti 3 Al content. The electrical conductivity and oxidation behavior of TiC-Ti 3 Al composites were investigated to evaluate the feasibility for SOFC interconnect application. The electrical conductivity measurements in the air at 800ºC for 100 hours were made using the Kelvin 4wire method.
The production of nanocrystalline Titanium carbide compound via mechanical alloying
2013
A nanocrystalline/nanoparticleTiCrefractorycompound has been produced by mechanical alloying (MA) of the elemental powders. The phase evolution and microstructural changes of the powders during mechanical alloying were investigated by means of X-ray diffractometry, field-emission scanning electron microscopy, highresolution transmission electron microscopy and microhardness measurements. The results showed that after an optimum mechanical alloying time of 15 hours, a TiCrefractorycompound with thecrystallite size of less than 10 nm, the particle size of about 80nm and the latticestrainof 1.8% was achieved.The obtained TiC refractorycompound exhibited high microhardness value of about 708 Hv. [Ali Seydi, Sepehr Pourmorad, Kave Arzani. The production of nanocrystalline Titanium carbide compound via mechanical alloying. Life Sci J 2012;9(4):5819-5823] (ISSN:1097-8135). http://www.lifesciencesite.com. 867
Titanium Carbide (TiC) Production by Mechanical Alloying
Powder Technology, 2018
This chapter presents the process for obtaining titanium carbides (TiC) from elemental powders of titanium dioxide, aluminum, and graphite by means of the mechanical alloying technique, using a semi-industrial attritor mill. Three grindings were performing: a wet, a dry, and a vacuum grinding. The mass relations between grinding elements and powders used were 20:1 to wet grinding and 40:1 to dry and vacuum grinding. Each grinding took 36 h with a control stop at 18 h. The samples were analyzed using X-ray diffraction analysis and the characteristics peak were detected on 2θ = 41, 60, 72, and 76°. Targets of TiC were produced using compaction and sintering processes. The particle size (between 200 nm and 1 μm) was measure using a scanning electron microscopy (SEM). After the milling process, the particle size showed a huge distribution. However, after the sintered process, the particle size (lower than 5 μm) distribution had a low dispersion and their shape trends to be spherical. It is necessary to highlight that the precursors used were low cost compared to the high cost and purity powders used for this purpose; so this method is an excellent alternative to implement as a low-cost industrial process.
Bulletin of Materials Science, 2016
TiAl-based intermetallic matrix composites with dispersed Ti 2 AlC particles and different amounts of Nb were successfully synthesized by mechanical alloying and hot pressing. The phase evolution of Ti-48 at%. Al elemental powder mixture milled for different times with hexane as a process control agent was investigated. It was found that after milling for 25 h, a Ti(Al) solid solution was formed; also with increase in the milling time to 50 h, an amorphous phase was detected. Formation of a supersaturated Ti(Al) solid solution after 75 h milling was achieved by crystallization of amorphous phase. Addition of Nb to system also exhibited a supersaturated Ti(Al,Nb) solid solution after milling for 75 h, implying that the Al and Nb elements were dissolved in the Ti lattice in a nonequilibrium state. Annealing of 75 h milled powders resulted in the formation of equilibrium TiAl intermetallic with Ti 2 AlC phases that showed the carbon that originates from hexane, participated in the reaction to form Ti 2 AlC during heating. Consolidation of milled powder with different amounts of Nb was performed by hot pressing at 1000 • C for 1 h. Only the presence of γ-TiAl and Ti 2 AlC was detected and no secondary phases were observed on the base of Nb. Displacement of γ-TiAl peaks with Nb addition implied that the Nb element was dissolved into TiAl matrix in the form of solid solution, causing the lattice tetragonality of TiAl to increase slightly. The values for density and porosity of samples indicated that condition of hot pressing process with temperature and pressure was adequate to consolidate almost fully densified samples. The isothermal oxidation test was carried out at 1000 • C in air to assess the effect of Nb addition on the oxidation behaviour of TiAl/Ti 2 AlC composites. The oxidation resistance of composites was improved with the increase in the Nb content due to the suppression of TiO 2 growth, the formation and stabilization of nitride in the oxide scale and better scale spallation resistance.
Spark plasma sintering consolidation of nanostructured TiC prepared by mechanical alloying
International Journal of Refractory Metals & Hard Materials, 2011
Spark plasma sintering technique was used for the consolidation of nanostructured titanium carbide synthesized by mechanical alloying in order to avoid any important grain growth of the compact materials. The TiC phase was obtained after about 2 h of mechanical alloying. Towards the end of the milling process (20 h), the nanocrystalline powders reached a critical size value of less than 5 nm. Some physical and mechanical properties of the consolidated carbide were reported as a function of the starting grain size powders obtained after different mechanical alloying durations. The crystalline grain size of the bulk samples was found to be increased to a maximum of 120 nm and 91 nm for carbides mechanically alloyed for 2 h and 20 h respectively. The Vickers hardness showed to be improved to about 2700 Hv for a maximum density of 95.1% of the bulk material.
Metals
Dense nanostructured carbides existing in ternary system Ti-Cr-C were elaborated thanks to a two-steps method. In the first step, nanostructured Ti0.9Cr0.1C carbides were prepared by high-energy planetary ball milling under various times (5, 10, and 20 h), starting from an elemental powder mixture of titanium, chromium, and graphite. In the second step, these nanostructured powders were used to produce densified carbides thanks to the spark plasma sintering (SPS) process under a pressure of 80 MPa. The temperature was fixed at 1800 °C and the holding time was fixed at 5 min. Microstructural characteristics of the samples were investigated using X-ray diffraction (XRD). Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) was used to investigate the morphology and elemental composition of the samples obtained using SPS. The novelty of this work is to understand the effect of SPS on the microstructural and electrochemical properties of the nanostr...