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, structure, and phase composition of Al-Al4C3 nanostructured materials

The morphology and phase composition of nanocrystalline powders of aluminum and carbon in the form of cluster diamonds are investigated. It is found that the hot compaction of the C-Al powder mixture is accompanied by the formation of an Al₄C₃ phase that has a highly disperse structure. The average crystallite size in hot-compacted materials is 40 nm for the metal matrix and 30 nm for aluminum. It is shown that as the carbon fraction in the initial powder mixture rises, the volume of the threshold space in hot-compacted materials increases.     

Modeling of two-phase flow of a gas mixture with burning metal particles in a semienclosed channel

Tomsk. Translated from Fizika Goreniya i Vzryva, Vol. 25, No. 3, pp. 39–43, May 1989.     

Two-stage method of synthesizing polyanthanthroylenebenzimidazole and preparation of a fibre based on it

Conclusions Polyanthanthroylenebenzimidazole has been prepared by a two-stage method. Some principles have been studied, and optimum conditions have been established for the first stage of the synthesis — preparation of the prepolymer.The possibility of cyclizing the prepolymer to polyanthanthroylenebenzimidazole has been demonstrated.Model yarn specimens have been prepared and a preliminary evaluation of their properties has been given.Translated from Khimicheskie Volokna, No. 1, pp. 29–32, January–February, 1987.     

Autoclave Molding of Thermoprotective Coatings on Large Products Using a Metal composite Mandrel

Russian Engineering Research - Abstract—A technology is developed for the application of a thermoprotective coating by autoclave molding with a metal composite mandrel. This technology...     

Low energy beam transport for facility for rare isotope beams driver linear particle accelerator

The driver linac for the facility for rare isotope beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research. The linac will be capable of accelerating a uranium beam to an energy of up to 200 Mev∕u and delivering it to a fragmentation target with a maximum power of 400 kW. Stable ion beams will be produced by a high performance electron cyclotron resonance ion source operating at 28 GHz. The ion source will be located on a high voltage platform to reach an initial beam energy of 12 keV∕u. After extraction, the ion beam will be transported vertically down to the linac tunnel in a low energy beam transport (LEBT) system and injected into a radio frequency quadrupole (RFQ) operating at a frequency of 80.5 MHz. To meet the beam power requirements, simultaneous acceleration of two-charge states will be used for heavier ions (≥Xe). This paper presents the layout of the FRIB LEBT and the beam dynamics in the LEBT. In particular, simulation and design of the beam line section before charge state selection will be detailed. The need to use an achromatic design for the charge state selection system and the advantage of an ion beam collimation system to limit the emittance of the beam injected into the RFQ will be discussed in this paper.     

Burning of Nano-Aluminized Composite Rocket Propellants

Several aluminum nanopowders were examined and compared with the final goal to evaluate their application in solid rocket propulsion. A detailed investigation of pre-burning properties by the Brunauer-Emmet-Teller method, electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy was carried out. Ballistic properties and the combustion mechanism of several aluminized propellant formulations were investigated. In particular, aggregation and agglomeration of metal particles at and near the burning surface were analyzed by high-speed high-resolution color digital video recordings. All tested nano-powders are of Russian production; their physical characterization was carried out at the Istituto Donegani (Novara, Italy); ballistic studies were performed at the Solid Propulsion Laboratory (Milano, Italy) using laboratory and, for comparison, industrial composite propellants based on ammonium perchlorate as an oxidizer. Results obtained under a fair variety of operating conditions typical of rocket propulsion indicate, for increasing nano-Al mass fraction or decreasing nano-Al size, larger steady burning rates with essentially the same pressure sensitivity. While aggregation and agglomeration phenomena still occur, their significance may be reduced by using nano-Al instead of micro-Al. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 6, pp. 80–94, November–December, 2005.     

On the properties of curvilinear shock waves “smearing” in calculations by the particle-in-cell method

It is shown by the 2-dimensional numerical computations of the cylindrical shock wave propagation using the particle-in-cell method tha the width of a “smeared” shock wave zone reaches its minimum at some non-zero inclination angle of the velocity vector with respect to the x-axis in the “smeared” shock wave. Results of theoretical analysis of the characteristics of the characteristics of the smeared shock wave zone width dependence upon the flow orientation with respect to the rectangular computing mesh lines carried out by the use of the first differential approximation method agree well with calculation results.