ID-158 FABRICATION OF Cu-Cr NANOCOMPOSITES FOR ELECTROTECHNICAL APPLICATIONS Natalia Shkodich(1),... more ID-158 FABRICATION OF Cu-Cr NANOCOMPOSITES FOR ELECTROTECHNICAL APPLICATIONS Natalia Shkodich(1), Alexander Rogachev(1), A. Mukasyan(2), D. Moskovskikh(3) (1)ISMAN, Russian Federation [email protected], [email protected] (2)University of Notre Dame, United States of America [email protected] (3)National University of Science and Technology “MISIS”, Russian Federation [email protected]
ABSTRACT An efficient approach that combines short-term (minutes) high-energy dry ball milling an... more ABSTRACT An efficient approach that combines short-term (minutes) high-energy dry ball milling and wet grinding to tailor the nano- and microstructure of Ni+Al composite reactive particles is reported. Varying the ball-milling conditions allows control of the volume fraction of two distinct milling-induced microstructures, that is, coarse and nanolaminated. It is found that increasing the fraction of nanolaminated structure present in the composite particles leads to a decrease in their ignition temperature (Tig) from 700 and 500 K. Material with nanolaminated microstructure is also found to be more sensitive to impact ignition when compared with particles with a coarse microstructure. It is shown that kinetic energy (Wcr) thresholds for impact ignition, obtained for an optimized nanolaminated microstructure, is only 100 J. High-speed imaging showed that the impact-induced ignition occurs through formation of hot spots caused by impact. Molecular dynamic simulations of a model system suggest that impact-induced localized plastic deformation raises the local temperatures to 600 K, enough to initiate exothermic reactions. Analysis of the kinetics and reaction mechanism shows that the reason for low Tig and Wcr for nanolaminated microstructure is the rapid solid-state dissolution of nickel in aluminum lattices.
INTRODUCTION. Among all implant materials, Co-Cr-Mo alloys demonstrate perhaps the most useful ba... more INTRODUCTION. Among all implant materials, Co-Cr-Mo alloys demonstrate perhaps the most useful balance of resistance to corrosion, fatigue and wear, along with strength and biocompatibility [1]. Currently, these widely used alloys are produced by conventional furnace technology. Owing to high melting points of the main alloy elements (e.g. Tm.p.(Co) ~1768 K), high-temperature furnaces and long process times (several hours) are required. Therefore, attempts to develop more efficient and flexible methods for production of such alloys with superior properties are of great interest. The synthesis of materials using combustion phenomena is an advanced approach in powder metallurgy [2]. The process is characterized by unique conditions involving extremely fast heating rates (up to 10 6 K/s), high temperatures (up to 3500 K), and short reaction times (on the order of seconds). As a result, combustion synthesis (CS) offers several attractive advantages over conventional metallurgical proces...
Combustion in a variety of heterogeneous systems, leading to the synthesis of advanced materials,... more Combustion in a variety of heterogeneous systems, leading to the synthesis of advanced materials, is characterized by high temperatures (2000-3500 K) and heating rates (up to 10(exp 6) K/s) at and ahead of the reaction front. These high temperatures generate liquids and gases which are subject to gravity-driven flow. The removal of such gravitational effects is likely to provide increased control of the reaction front, with a consequent improvement in control of the microstructure of the synthesized products. Thus, microgravity experiments can lead to major advances in the understanding of fundamental aspects of combustion and structure formation under the extreme conditions of the combustion synthesis wave. In addition, the specific features of microgravity environment allow one to produce unique materials, which cannot be obtained under terrestrial conditions. The general goals of the current research are: 1) to improve the understanding of fundamental phenomena taking place durin...
Here, we report ultra-fast (0.1-5 ls) shock-induced reactions in the 3B-TiN system, leading to th... more Here, we report ultra-fast (0.1-5 ls) shock-induced reactions in the 3B-TiN system, leading to the direct synthesis of cubic boron nitride, which is extremely rare in nature and is the second hardest material known. Composite powders were produced through high-energy ball milling to provide intimate mixing and subsequently shocked using an explosive charge. High-resolution transmission electron microscopy and X-ray diffraction confirm the formation of nanocrystalline grains of c-BN produced during the metathetical reaction between boron and titanium nitride. Our results illustrate the possibility of rapid reactions enabled by high-energy ball milling possibly occurring in the solid state on incredibly short timescales. This process may provide a route for the discovery and fabrication of advanced compounds.
New classes of reactive systems that are characterized by nano-scale heterogeneity and possess ex... more New classes of reactive systems that are characterized by nano-scale heterogeneity and possess extremely high reactivity, as compared to that for similar reactive systems with micro-scale heterogeneity, have attracted a vast attention of many researchers. The recent developments and trends in combustion science towards such "nano" reactive media are presented. These systems include mechanically induced composite particles, sol-gels, super thermites and multilayer nanofoils. Various combustion-based applications of such nanostructured reactive systems are also discussed.
International Journal of Self-Propagating High-Temperature Synthesis, 2015
A new electrothermographic method, viz. high speed temperature scanning, was applied to kinetic s... more A new electrothermographic method, viz. high speed temperature scanning, was applied to kinetic studies of reactions taking place in the Ni-Al system, including those after mechanical activation in a planetary ball mill. Treatment of the temperature profiles taken at different heating rates in terms of the Kissinger-Akahira-Sunose (KAS) approximation gave activation energy E for non activated mixtures: E = 155 kJ/mol (for temperature range 650-850°C). But for mechanically activated mixtures, the characteristic points (reaction onset temperature, temperature of maximum reaction rate) were found to decrease with increasing heating rate, which makes the KAS method inapplicable to these compositions. It has been con cluded that mechanical treatment leads to significant changes in the reaction kinetics, possibly due to split ting the reaction route into two stages the first of which has very low activation energy.
High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ba... more High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.
47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 2011
Aluminized composite propellants have long suffered from efficiency and thermal challenges relate... more Aluminized composite propellants have long suffered from efficiency and thermal challenges related to production of condensed phase slag droplets during operation. In an effort to mitigate the production of large droplets, a mechanically activated intermetallic forming nickel-aluminum compound was substituted for a portion of a propellant's aluminum fuel. The resulting agglomerate size and burning rate of this propellant was compared to a standard aluminized AP/HTPB propellant. Addition of mechanically activated fuel particles increased the burning rate exponent of the propellant, while simultaneously decreasing condensed phase agglomerate size from 235 µm (for the control propellant) to 90 µm (for the propellant containing 75 wt.% Ni-Al fuel). As such, intermetallic forming fuels may provide a route for increasing efficiency in solid rocket motors by simultaneously reducing the need for burning rate catalysts and minimizing two-phase nozzle flow losses.
APS Bulletin of the American Physical Society. 16th APS Topical Conference on Shock Compression o... more APS Bulletin of the American Physical Society. 16th APS Topical Conference on Shock Compression of Condensed Matter Volume 54, Number 8. SundayFriday, June 28July 3 2009; Nashville, Tennessee. ...
ID-158 FABRICATION OF Cu-Cr NANOCOMPOSITES FOR ELECTROTECHNICAL APPLICATIONS Natalia Shkodich(1),... more ID-158 FABRICATION OF Cu-Cr NANOCOMPOSITES FOR ELECTROTECHNICAL APPLICATIONS Natalia Shkodich(1), Alexander Rogachev(1), A. Mukasyan(2), D. Moskovskikh(3) (1)ISMAN, Russian Federation [email protected], [email protected] (2)University of Notre Dame, United States of America [email protected] (3)National University of Science and Technology “MISIS”, Russian Federation [email protected]
ABSTRACT An efficient approach that combines short-term (minutes) high-energy dry ball milling an... more ABSTRACT An efficient approach that combines short-term (minutes) high-energy dry ball milling and wet grinding to tailor the nano- and microstructure of Ni+Al composite reactive particles is reported. Varying the ball-milling conditions allows control of the volume fraction of two distinct milling-induced microstructures, that is, coarse and nanolaminated. It is found that increasing the fraction of nanolaminated structure present in the composite particles leads to a decrease in their ignition temperature (Tig) from 700 and 500 K. Material with nanolaminated microstructure is also found to be more sensitive to impact ignition when compared with particles with a coarse microstructure. It is shown that kinetic energy (Wcr) thresholds for impact ignition, obtained for an optimized nanolaminated microstructure, is only 100 J. High-speed imaging showed that the impact-induced ignition occurs through formation of hot spots caused by impact. Molecular dynamic simulations of a model system suggest that impact-induced localized plastic deformation raises the local temperatures to 600 K, enough to initiate exothermic reactions. Analysis of the kinetics and reaction mechanism shows that the reason for low Tig and Wcr for nanolaminated microstructure is the rapid solid-state dissolution of nickel in aluminum lattices.
INTRODUCTION. Among all implant materials, Co-Cr-Mo alloys demonstrate perhaps the most useful ba... more INTRODUCTION. Among all implant materials, Co-Cr-Mo alloys demonstrate perhaps the most useful balance of resistance to corrosion, fatigue and wear, along with strength and biocompatibility [1]. Currently, these widely used alloys are produced by conventional furnace technology. Owing to high melting points of the main alloy elements (e.g. Tm.p.(Co) ~1768 K), high-temperature furnaces and long process times (several hours) are required. Therefore, attempts to develop more efficient and flexible methods for production of such alloys with superior properties are of great interest. The synthesis of materials using combustion phenomena is an advanced approach in powder metallurgy [2]. The process is characterized by unique conditions involving extremely fast heating rates (up to 10 6 K/s), high temperatures (up to 3500 K), and short reaction times (on the order of seconds). As a result, combustion synthesis (CS) offers several attractive advantages over conventional metallurgical proces...
Combustion in a variety of heterogeneous systems, leading to the synthesis of advanced materials,... more Combustion in a variety of heterogeneous systems, leading to the synthesis of advanced materials, is characterized by high temperatures (2000-3500 K) and heating rates (up to 10(exp 6) K/s) at and ahead of the reaction front. These high temperatures generate liquids and gases which are subject to gravity-driven flow. The removal of such gravitational effects is likely to provide increased control of the reaction front, with a consequent improvement in control of the microstructure of the synthesized products. Thus, microgravity experiments can lead to major advances in the understanding of fundamental aspects of combustion and structure formation under the extreme conditions of the combustion synthesis wave. In addition, the specific features of microgravity environment allow one to produce unique materials, which cannot be obtained under terrestrial conditions. The general goals of the current research are: 1) to improve the understanding of fundamental phenomena taking place durin...
Here, we report ultra-fast (0.1-5 ls) shock-induced reactions in the 3B-TiN system, leading to th... more Here, we report ultra-fast (0.1-5 ls) shock-induced reactions in the 3B-TiN system, leading to the direct synthesis of cubic boron nitride, which is extremely rare in nature and is the second hardest material known. Composite powders were produced through high-energy ball milling to provide intimate mixing and subsequently shocked using an explosive charge. High-resolution transmission electron microscopy and X-ray diffraction confirm the formation of nanocrystalline grains of c-BN produced during the metathetical reaction between boron and titanium nitride. Our results illustrate the possibility of rapid reactions enabled by high-energy ball milling possibly occurring in the solid state on incredibly short timescales. This process may provide a route for the discovery and fabrication of advanced compounds.
New classes of reactive systems that are characterized by nano-scale heterogeneity and possess ex... more New classes of reactive systems that are characterized by nano-scale heterogeneity and possess extremely high reactivity, as compared to that for similar reactive systems with micro-scale heterogeneity, have attracted a vast attention of many researchers. The recent developments and trends in combustion science towards such "nano" reactive media are presented. These systems include mechanically induced composite particles, sol-gels, super thermites and multilayer nanofoils. Various combustion-based applications of such nanostructured reactive systems are also discussed.
International Journal of Self-Propagating High-Temperature Synthesis, 2015
A new electrothermographic method, viz. high speed temperature scanning, was applied to kinetic s... more A new electrothermographic method, viz. high speed temperature scanning, was applied to kinetic studies of reactions taking place in the Ni-Al system, including those after mechanical activation in a planetary ball mill. Treatment of the temperature profiles taken at different heating rates in terms of the Kissinger-Akahira-Sunose (KAS) approximation gave activation energy E for non activated mixtures: E = 155 kJ/mol (for temperature range 650-850°C). But for mechanically activated mixtures, the characteristic points (reaction onset temperature, temperature of maximum reaction rate) were found to decrease with increasing heating rate, which makes the KAS method inapplicable to these compositions. It has been con cluded that mechanical treatment leads to significant changes in the reaction kinetics, possibly due to split ting the reaction route into two stages the first of which has very low activation energy.
High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ba... more High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.
47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 2011
Aluminized composite propellants have long suffered from efficiency and thermal challenges relate... more Aluminized composite propellants have long suffered from efficiency and thermal challenges related to production of condensed phase slag droplets during operation. In an effort to mitigate the production of large droplets, a mechanically activated intermetallic forming nickel-aluminum compound was substituted for a portion of a propellant's aluminum fuel. The resulting agglomerate size and burning rate of this propellant was compared to a standard aluminized AP/HTPB propellant. Addition of mechanically activated fuel particles increased the burning rate exponent of the propellant, while simultaneously decreasing condensed phase agglomerate size from 235 µm (for the control propellant) to 90 µm (for the propellant containing 75 wt.% Ni-Al fuel). As such, intermetallic forming fuels may provide a route for increasing efficiency in solid rocket motors by simultaneously reducing the need for burning rate catalysts and minimizing two-phase nozzle flow losses.
APS Bulletin of the American Physical Society. 16th APS Topical Conference on Shock Compression o... more APS Bulletin of the American Physical Society. 16th APS Topical Conference on Shock Compression of Condensed Matter Volume 54, Number 8. SundayFriday, June 28July 3 2009; Nashville, Tennessee. ...
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