Hydrogenation process in multiphase alloys of Ti-Zr-Mn-V system on the example of Ti42.75Zr27Mn20.25V10 alloy

The influence of phase composition and microstructure of Ti_42.75Zr₂₇Mn_20.25V₁₀ alloy on its hydrogenation kinetic and phase composition of hydrogenated product was studied. It is established that the process of dissociation of hydrogen molecules begins on the surface of Laves phase crystallites. The dissolution of atomic hydrogen in the material volume leads to the formation of cracks in the intermetallic crystallites, which further appear as additional centers of dissociation of hydrogen molecules and noticeably accelerate the diffusion of hydrogen into the bulk material. It was shown that the Laves phase acts as a donor of atomic hydrogen for the BCC solid solution during hydrogenation of two-phase structure, initiating intensive hydrogenation of the BCC phase at room temperature.     

Mechanisms of high-strain-rate deformation and fracture of fine-grained unalloyed uranium upon explosive loading

The study of the microstructure and properties of quasi-statically extruded fine-grained uranium before and after explosive loading has shown that the main mechanism of its high-strain-rate deformation is multiple twinning. The nucleation of spall and shear microdamages upon explosive loading occurs at oxycarbonitride inclusions, just as in the coarse-grained cast metal upon the analogous regime of explosive loading. The absence of an increase in the spall strength of uranium upon a decrease in the initial grain size by a factor of 100–250 is related to the presence of a significant amount of impurities (to 1.5 ± 0.2 vol %) in the material.     

Comparative Analysis of Methods for Measuring the Transient Burning Rate. II. Research Results

This paper considers two independent methods for measuring the transient burning rate of solid propellants-high-speed photography and a method based on solving the inverse problem of interior ballistics. Comparative analysis shows that these methods are mutually complementary. Evaluation of the ranges of application of the inverse methods of identifying the transient burning rate shows that their use is promising not only in laboratory tests but also in measurements in large solid propellant gas generators.     

Influence of zirconium and nitrogen on the structure and properties of surfaced chromium metal

Conclusion With simultaneous microalloying with 0.013% Y, 0.05% Zr, and 0.075% N, the volume share of twinned martensite increases, the packets of dislocation martensite decrease, and a significant quantity of finely dispersed carbonitride particles is formed, which has a positive influence on the service properties of type 15Kh8N2M1FT surfaced metal.E. O. Paton Electric Welding Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 33–37, August, 1993.     

A capacitor cell of a capacitive energy storage with a switch based on reverse switch-on dynistors

A capacitor cell of a capacitive energy storage designed for operating with an arc load is described. The cell that stores an energy of 64 kJ is based on a high-voltage (18 kV) capacitor and allows formation of current pulses with an amplitude of up to 60 kA. The discharge circuit of the cell contains a semiconductor switch in the form of an assembly of reverse switch-on dynistors (RSDs) connected in series, a crowbar diode switch, and a replaceable toroidal inductor. An assembly of protecting diodes connected in series to the RSD switch excludes the possibility of a flow of reverse-current pulses through dynistors. All elements of the cell are mounted on the capacitor and occupy a volume of 120 dm³.     

Microstructure and mechanical characteristics of VT1-0 alloy after rapid surface heat treatment

We study the distinctive features of the formation of microstructure and mechanical properties of VT1-0 commercially pure titanium subjected to rapid surface heat treatment. In a layer of the metal suffering the α → β → α transformation, we observe the formation of an α-structure with larger grain sizes and a somewhat lower microhardness, whereas in the transition zone, between the layers heated to temperatures above and below the temperature of the polymorphic transformation {ie368-01}, the microhardness increases. The increase in the volume fraction of the layer heated to a temperature above {ie368-02} is accompanied by a monotonic elevation of the strength properties and deterioration of the plastic characteristic of the metal. In the case of 100% heating above {ie368-03}, the fatigue limit of the metal becomes 1.5 times higher. On the basis of the accumulated results, we make a conclusion that the changes in the mechanical characteristics of the alloy are connected with the formation of thermal compression stresses caused by very rapid processes of heating and cooling of the metal (up to 400°C/sec). Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 44, No. 3, pp. 57–61, May–June, 2008.     

Current problems in organizing the donor system in the Armed Forces

In the work the factors, rendering essential influence on organization of donorship in modern army conditions are systematized. The organization of donorship should be connected to functioning of territorial system of medical maintenance of the Armed Forces of RF. It assumes presence of four organizational levels: central, district, zone and garrison. Perfecting the system of organization of donorship, we should be guided by the following conducting principles: maximum maintenance of safety of donorship; wide introduction of a method of plasmacytopheresis in work of establishments and subdivisions of blood supply service; organization of autodonorship and quota of the donors of an emergency reserve in each military-medical establishment; reliable maintenance of revealing of markers of hemotransmissible infections at inspection of the donors.