614 research outputs found
Light metals and their composites
It is known that metallurgy influences almost all sectors of industry, including energy, aeronautics, automotive, space, chemical, machinery, scientific equipment, construction, packaging, electrical, computing and health. Without metals and alloys, the modern world would be inconceivable and could not function successfully. The importance of lightweighting in the transport sector, as an effective way of cutting greenhouse gas (GHG) emissions, cannot be overstated. As an example of weight-saving potential, a 100 kg weight reduction for a long-haul aeroplane saves about 20,000 gigajoules of energy and 1,900,000 kg of CO2 emissions over its 30-year lifetime. Similarly, a 100 kg weight reduction for an average car saves about 25 gigajoules and 1600 kg of CO2 over its 10-year lifetim
A New QF1 Magnet for ATF3
Two high field quality quadrupole magnets QF1FF and QD0FF are required for
the final focus system of the ATF3. In this paper we focus on the design of the
QF1FF magnet. The proposed design is a permanent magnet quadrupole (PMQ) with
adjustable strength. Alternative solutions such as conventional electromagnetic
quadrupole (EMQ) and a hybrid quadrupole (combination of permanent magnet and
electromagnet) are also presented and briefly discussed.Comment: 11 pages, Contribution to LCWS11 Workshop Granada, Spain 201
Theoretical and experimental investigations of the process of vibration treatment of liquid metals containing nanoparticles
It is known that the use of external effects, such as acoustic fields (from ultrasonic to low-frequency range), help in breaking down agglomerates, improving particle wettability, providing uniform particle distribution in the melt volume, and reducing the grain size. The fragmentation of growing crystals, de-agglomeration of particles and their mixing in liquid metal under the influence of vibration (with frequencies of 10–100 Hz) are considered in this paper. The major advantage of such a technique in comparison with high-frequency methods (sonic, ultrasonic) is the capability of processing large melt volumes proportional to the wavelength. The mechanisms of the breaking down of particle agglomerates and the mixing of particles under conditions of cavitation and turbulence during the vibration treatment of the melt are considered. Expressions linking the threshold intensity and frequency with the amplitude necessary to activate mechanisms of turbulence and cavitation were obtained. The results of vibration treatment experiments for an aluminum alloy containing diamond nanoparticles are given. This treatment makes it possible to significantly reduce the grain size and to improve the casting homogeneity and thus improve the mechanical properties of the alloy
Shock-wave synthesis and properties of MMC reinforced with Al2O3, AlN and AlB2 (nano) particles
Self-propagating high-temperature synthesis of energetic borides
A promising way to synthesize new energy materials based on refactory inorganic compounds is self-propagating high-temperature synthesis of compositions based on boron compounds. This paper describes a laboratory technology of production of aluminum borides. The experimental results of thermogravimetric analysis and particle size analysis obtained for synthesized powders are given. According to thermogravimetric analysis data the degree of oxidation of obtained powders exceeds 95 %. The experimental data have shown that the development of new compositions of high-energy fuel cells using borides can yield high-quality results in the sphere of solid hypersonic engines
Influence of static tensile testing on the deformation behavior of Al–4% Cu alloy containing micro- and nanoparticles
At present, aluminum alloys reinforced with nonmetallic particles are of great interest in various fields of science and technology due to their high specific strength, hardness, wear resistance, and other properties. At the same time there is a great interest in the study of processes occurring during plastic deformation of such materials under static tensile loading. Plastic flow of metals occurs through the creation and movement of linear defects (dislocations), in which there is a phenomenon of discontinuous yielding. An introduction of particles into aluminum alloy promotes a considerable increase of stiffness and specific strength of alloys, and the study of the deformation behavior of such alloys is of great interest. The objective of this research is to analyze mechanical properties and the deformation behavior of aluminum alloy with the identification of mechanisms of plastic deformation when introducing solid nonmetallic micro- and nanoparticles into the soft aluminum matrix. An analysis of the microstructure of the obtained alloys shows that the introduction of particles (Al2O3, TiB2, TiC) leads to a reduction of the alloy grain size from 350 to 170 µm while residual porosity does not exceed 2%. Tensile tests performed show that the change in the type and quantity of particles also changes characteristics of discontinuous yielding, thus resulting in an increase of yield strength (from 18 to 40 MPa), reduction of ductility (from 15 to 2%), and moreover a significant increase of tensile strength (from 77 to 130 MPa), as compared to the initial Al–4 wt % Cu alloy
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