Papers by Keyword: Structure

Abstract: Structural properties of porous TiNi-based materials produced by SHS method and sintering have been investigated. The material having different pore wall surface topography, porosity and pore size distribution was shown to be produced depending on the powder metallurgy method for porous TiNi-based alloy. All the materials having porosity of 55-70%, mean pore size 90-150 μm, as well as normal pore size distribution are most preferable. Ultimate strength and breaking point were determined to depend on porosity, pore size distribution, pore intersections and phase chemical composition of the material. Strength properties of the sintered alloy are twice as much compared to the SHS-produced ones due to homogeneity of its macrostructure, low chemical heterogeneity and TiNi₃ precipitations strengthening the TiNi matrix.

Abstract: Ceramics samples in the form of a parallelepiped with high strength characteristics have been made. For the manufacture of the ceramics samples a powder mixture from submicron В4С powder with additives (1 wt%, 5 wt%, 10 wt%) of boron carbide nanopowder was used. The physical properties of the powder mixtures and strength properties of sintered ceramics have been studied. It was shown that the use of submicron fractions of the boron carbide powder together with nanoadditives is a determining factor in the formation of dense fine-grained structure providing improved physical and mechanical properties of the ceramics.

Abstract: The alloying of the titanium layer by yttrium is carried out with the combined method of electroexplosive alloying and the subsequent radiation by a high-intensity electron beam. The research of structure, element and phase composition, mechanical and tribological properties of the alloyed layer is executed. The saturation of the titanium layer by atoms of yttrium, oxygen and carbon that leads to formation of oxides and carbides of the titanium and yttrium is revealed. The formation of two types of an eutectic is established. It is shown that the eutectic enriched with the titanium has a globular form when the eutectic enriched with yttrium has a plated one. The multiple increasing of microhardness, decreasing of friction coefficient and the wear rate of the alloyed layer is revealed.

Abstract: The results of the X-ray phase and thermodynamic analysis of phase formation in the Zr-Y-O system which is the initial material for formation of yttrium of stabilized ceramics on the basis of dioxide of zirconium are presented. It is established that the material is multiphase and contains monoclinic, cubic and tetragonal modifications of dioxide of zirconium which weight ratios differ considerably.

Abstract: Modification of a titanium surface layer with yttrium using the combined technique of electroexplosive doping and the subsequent irradiation by a high-intensity electron beam is carried out. The studies on the structure, the element and the phase composition, mechanical and tribological properties of the doped layer are carried out. Formation of a multiphase submicron-nanocrystalline eutectic is revealed. A multifold increase in the microhardness, a decrease in the friction coefficient and the wear rate of the modified layer is established.

Abstract: In order to study the influence of muscle structural changes on the special brittleness mechanism of crisp grass carp (Ctenopharyngodon idellus C.et V, CGC) during different crisping process of grass carp (Ctenopharyngodon idellus, GC), samples were periodically acquired and then prepared for light and transmission electron microscopy during the whole process. For GC and CGC, all muscle tissues had typical features, whereas there were much more interstitial tissues and narrower intermyofibrillar spaces in CGC than those in GC. Meanwhile, the muscle fibers diameter, intermyofibrillar space and myofibrils to endomysium detachment lengths of GC were significantly decreased with increasing duration of crisping time. While the muscle fibers density and sarcomere lengths were significantly greater in CGC than in GC. In view of the structural and ultra-structural differences in these samples, it was conceivable to suggest that short muscle fiber diameter, high fiber density, narrow intermyofibrillar spaces and wide lengths of sarcomere were the main causes of increased muscle brittleness.

Abstract: In the Paper, an analysis of laser modification of the surface of specimens produced of powder steel 1.2083 by SLS (selective laser sintering) method is carried out. Three main structures being formed on laser modification of the sintered steels are presented: periodical, interim and degrading. The dependence of the changes of the technological parameters of the laser equipment on the geometrical parameters of the specimen under processing is provided.

Abstract: This paper proposes the dynamic design method and process of a CNC lathe-bed structure based on ansys. The lathe-bed is an important part of lathe. Structural natural frequency as the objective of optimization, with the element structure and frame structure optimization result as the basis, and with a vertical machining center lathe as an example, we put forward some improvement scheme of the bed structure, and makes a comparative analysis of each scheme.

Abstract: This article introduces the significance of studying the Micro-grid, the definition, the characteristics ,the basic structure,the architecture and working principle of Micro-grid. Discuss the Micro-grid constitutes, including loads, distributed generation,etc. At last, it points out the disadvantages and the directions of Micro-grid, we should come to a unified definition of Micro-grid and a unified protection program and configuration,in order to get ready for the early Micro-grid research.

Abstract: A new variable structure chamber was designed to plasma reaction with two-stage showerhead, and its flow filed dynamic control equation was analyzed and meshed by ICEM. The simulation research for the meshed models was analyzed by a commercial software-Fluent, by changing various parameters such as mass flow inlet, height, diameter and section of outlet. The result shows that the height and diameter variation for chamber has a little influence on the pressure upon susceptor. However, when the mass flow increases in inlet, the pressure improves, and it also changes as the section variation of outlet.