The method of the high voltage electric discharge (HVED) treatment in the kerosene (the dispersion, the activation and the synthesis) is proposed to obtain the new anti-friction alloys based on TiC – AlC – and FeC with inclusions of the Cn0 (n=6 or 7) phases which are characterized by the high heat resistance, the strength and the durability to be used in the aircraft and in the rocket technology. The method is distinguished by the hardening particles, which are not mechanically added to the powder mixture, but instead they are synthesized during the HVED treatment of the “kerosene – Fe (Al) – Ti powder mixture” the disperse system with its simultaneous grinding what enable us to create the composite material with the increased mechanical and performance characteristics. The obtained alloys contain the refractory components (the fullerenes, the carbides), the MAX-phases of the Ti-Al-C system as shown by the micro-Raman data.
1 December 2016 in High Temperature Materials and Processes
High voltage electric discharge (HVED) in disperse system “hydrocarbon liquid – powder” due to impact of plasma discharge channel, electromagnetic fields, shock waves mechanical impact, hydro flows and volume microcavitation leads to synthesis of nanocarbon, metal powders dispersion and synthesis of micro- (from 10−6 to 10−7 m) and nanosized (from 10−7 to 10−9 m) composite powders of hardening phases. Spark plasma sintering (SPS) of powder mixtures allows targeted control of grain growth rate and thus allows obtainment of multifunctional composite materials dispersion hardened by nanoparticles. Processes of HVED synthesis of micro- and nanosized powders of new compositions from elemental metal powders and their mixtures with the subsequent application of high-speed SPS of obtained powders create conditions for increase of strength (by 10–20 %), hardness and wear-resistance (by 30–60 %) of obtained materials.
Dispersion-hardened materials based on TiC–AlnCn are alloys with high heat resistance, strength, and durability that can be used in aircraft and rocket technology as a hard lubricant. The titanium-rich composites of the Ti–Al–C system were synthesized via the spark plasma sintering process. Composite powder with 85% of Ti, 15% of Al, and MAX-phases was processed using high-voltage electrical discharge in kerosene at a specific energy of 25 MJ kg−1 to obtain nanosized particles. This method allows us to analyze the most efficient, energy saving, and less waste-generating technological processes producing materials with improved mechanical and physical properties. An Innova test indentation machine was used to determine the hardness of the synthesized composites. The microhardness of Ti–Al–C system samples was determined as approximately 500–600 HV. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were performed to identify the hard titanium matrix reinforced by intermetallic phases and the clusters of carbides. Three types of reinforcing phases were detected existing in the composites—TiC, Al4C3, and Al3Ti, as well as a matrix consisting of α- and β-titanium. The lattice parameters of all phases detected in the composites were calculated using Rietveld analysis. It was determined that by increasing the temperature of sintering, the amount of aluminum and carbon increases in the carbides and intermetallic phases, while the amount of titanium decreases.
1 March 2011 in Powder Metallurgy and Metal Ceramics