Alexander Vorozhtsov

The Application of External Fields to the Manufacturing of Novel Dense Composite Master Alloys and Aluminum-Based Nanocomposites

The possibility of producing dense and concentrated master alloys containing nanosized Al2O3 by shock-wave compacting is demonstrated. Different conditions of shock-wave process are discussed. The data of master alloys characterization are presented. The nanostructured master alloys have high density and are convenient for metallurgical handling. It is found that the use of such a master alloy with nanoceramic particles facilitates the particle introduction into the aluminum melt. The ultrasonic treatment performed during and after the introduction of the master alloy into the melt further leads to uniform distribution of strengthening nanoparticles and improvement of alloy strength and ductility. Experimental results are shown and discussed.

The ExoMet Project: EU/ESA Research on High-Performance Light-Metal Alloys and Nanocomposites

The performance of structural materials is commonly associated with such design parameters as strength and stiffness relative to their density; a recognized means to further enhance the weight-saving potential of low-density materials is thus to improve on their mechanical attributes. The European Community research project ExoMet that started in mid-2012 targets such high-performance aluminum- and magnesium-based materials by exploring novel grain refining and nanoparticle additions in conjunction with melt treatment by means of external fields (electromagnetic, ultrasonic, and mechanical). These external fields are to provide for an effective and efficient dispersion of the additions in the melt and their uniform distribution in the as-cast material. The consortium of 27 companies, universities, and research organizations from eleven countries integrates various scientific and technological disciplines as well as application areas—including automotive, aircraft, and space. This paper gives an overview of the project, including its scope for development and organization. In addition, exemplary results are presented on nanoparticle production and characterization, mixing patterns in metal melts, interface reactions between metal and particles, particle distribution in the as-cast composite materials, and mechanical properties of the as-cast composite materials. The application perspective is considered as well.

Synthesis of Micro- and Nanoparticles of Metal Oxides and Their Application for Reinforcement of Al-Based Alloys

This paper presents a comparative analysis of morphology, chemical and phase compositions, and particle size distribution of nanopowders produced by electric explosion of wire (EEW) and plasma-chemical methods. The possibility of introduction of Al2O3 particles into Al alloy by means of a special master alloy and with ultrasonic processing is shown. The improvement of tensile properties of an Al-based composite material reinforced with 0.1 wt% of EEW Al2O3 is demonstrated.

The Physical‐Mechanical Properties of Aluminum Nanocomposites Produced by High Energy Explosion Impact

The present paper uses explosion compacting of Al nanoparticles to create light nanocomposite with increased physico-mechanical properties. Russian civil explosive Uglenit was chosen as high energy material for compacting. The formation of the structure and properties of aluminum based materials after shock-wave impact was studied. It was found that shock-wave treatment of different samples a) aluminum powder and b) powder mixtures Al +10 wt.% C (in the form of detonation diamonds) and c) Al +10 wt.% Al2O3 produces nanostructed materials with almost the theoretical density. X-ray diffraction analysis showed that in the samples with the addition of carbon and aluminum oxide was formed two-phase state of aluminum with a significantly different structure parameters. In this case, the lattice parameter of nanophase increased by 0.5%, which testifies to its nonequilibrium state. This increase of the parameter may be due to compressive stress, evaluation of which gives the value of 350 MPa. It was shown that the materials have high values of mechanical properties — hardness, compressive yield strength.

Novel Micro- and Nanofuels: Production, Characterization, and Applications for High-Energy Materials

In this paper, the problems of production and characterization of nanosized metals (nanosized aluminum) and microsized metal borides (including aluminum, titanium, magnesium) are discussed. The preferences of application for high-energy materials are presented. Also, the technique for production of nanometals is described which is the electric explosion wire method. The results of characterization of nanometals produced by that method are shown and discussed. To protect an active surface of nanoparticles, the different ways for passivation are suggested. Different polymers including Viton and Fluorel are suggested as passivated agents. The problems of chemical stability and chemical compatibility are discussed. A technique for production of metal borides is also described which is known as self-propagating high-temperature synthesis (SHS) and the subsequent mechanical treatment. The result is microsized borides which have an average size of around 5 μm with a sharp curve for distribution sizes. The purity is enough for use as fuel of high-energy materials. The results of TEM, SEM, X-ray, DSC, and TG analyses are also presented and discussed.

Thermal Shock-Resistant Ceramic Composites Based on Zirconium Dioxide1

Changes in structure, phase composition and crystal structure parameters are studied for materials of the ZrO2–MgO system after cyclic thermal shock effects. Features are revealed for formation of ceramic structure and phase condition with implementation of internal stresses connected with a sharp change in temperature. Optimum compositions are established for refractory materials based on ZrO2 answering high specifications for thermal shock resistance and refractoriness.

Plasma-chemical method for producing metal oxide powders and their application

Structure and properties of ZrO2 and Al2O3 powders produced using plasma chemical technique were studied in the framework of this research. Obtained Al2O3 powder was used for reinforcement of Al alloy. Improvement of mechanical properties of Al alloy associated with introduction of alumina particles into the melt was demonstrated.

Synthesis and Properties of Energetics Metal Borides for Hybrid Solid-Propellant Rocket Engines

In this paper, the problems of production and characterization of microsized metal borides (including aluminum, titanium, magnesium) are discussed. The preferences of application for high-energy materials are presented. The problems of chemical stability and chemical compatibility are discussed. A technique for production of metal borides is also described which is known as self-propagating high-temperature synthesis (SHS) and the subsequent mechanical treatment. The result is microsized borides which have an average size of around 5 microns with a sharp curve for distribution sizes. The purity is enough for use as fuel of high-energy materials hybrid solid-propellant rocket engines. The results of SEM, X-Ray, DSC, and TG analyses are also presented and discussed.

On the possibility to fabricate ceramics using fused deposition modeling

The paper presents a uniquely designed device that enables controlled manufacturing of semi-fabricated products from thermoplastic ceramic suspensions by fused deposition modeling. Sintering of the products yields ceramics with high strength and hardness. We use ceramic aluminum oxide (Al2O3) as an example to prove that additive ceramic structures can be produced without noticeable boundaries between layers of the material.

The Use of Alumina and Zirconia Nanopowders for Optimization of the Al-Based Light Alloys

The paper presents data on the structure, phase composition and other properties of zirconia and alumina powders obtained by electric explosion of wire and plasma-chemical deposition methods. Scanning and transmission electron microscopy reveal that the nanoscale powders are composed of spherical particles and aggregates formed by these particles. X-ray diffraction is used to identify the parameters of the crystal structure of these powders. Specific surface area is determined for all powders by BET method. Powders are used to improve the mechanical properties of aluminum alloys. For the optimization of introduction reinforcement nanoparticles used ultrasonic treatment of the melt.