Effect of the method of production of an Ni<Subscript>3</Subscript>Al/Mo layered composite material on its structure and properties

A stack of alternating 25 100-μ-thick Ni₃Al plates and 28 200-μm-thick Mo plates is subjected to hot isostatic pressing (HIP) at a temperature T = 1200°C and a pressure P = 150 MPa for τ = 2.5 h followed by hot rolling at 1050–950°C to a thickness of 2.3 mm. The stack is then subjected to cold rolling (CR) to a thickness of 0.5 mm without intermediate annealing, subsequent annealing during HIP at T = 1200°C, P = 150 MPa, and τ = 2.5 h, and CR to a thickness of 0.22 mm. Upon CR at a strain ε changing from 80.8 to 95.8%, the following specific structure forms in the longitudinal direction: molybdenum layers acquire a wavelike structure, can contact with each other, form “cells,” and retain almost the same thickness, and Ni₃Al alloy layers are rejected between the molybdenum layers to form a regular structure made of alternating thickenings and thinnings across the rolling direction. Annealing during HIP and subsequent CR to ε = 98.2% lead to the formation of zones with a broken alternation of layers in the longitudinal and transverse directions, which is related to different strain resistances of the (more refractory) molybdenum and Ni₃Al layers at 20°C. The adhesion between the layers is good, and no intermediate phases form at the interface. The ultimate bending strength of the 2.3-mm-thick workpiece at 20°C is 1000 ± 100 MPa, and the prepared material has a plasticity margin.     

An automatic system for controlling the UV-radiation dose

A photodetector based on an ⁺-GaAs/n-ClInPc heterojunction, photosensitive in the 200- to 1000-nm wavelength range, is described. The ClInPc absorbtance is high:K _λ=2×10⁷ m⁻¹ for λ=220 and 380 nm. The photosensitivity of the photodetector is 2250 V/W (S=1 cm²). An automatic system for controlling the UV-radiation dose was developed on the basis of this photoreceiver.     

A compact high-voltage nanosecond marx generator based on air-field dischargers

Results of the development and study of a 14-stage air high-voltage pulse generator with an output voltage of up to 250 kV, a current rise time of 10 ns, and blow capacitance of 400 pF are presented. The design and the schematic circuit diagram of the generator are described.     

The DEVIS track detector developed by the Institute for Theoretical and Experimental Physics for studying double β decay

The DEVIS setup, consisting of a time projection chamber placed in a magnetic field, is designed to study the 2 decay of ¹³⁶Xe atoms. The sensitivity of the setup was assessed in a set of measurements using Xe with natural isotopic composition. The setup will allow observations of the two-neutrino double decay of ¹³⁶Xe with a half-life of <3 × 10²⁰ yr.__________Translated from Pribory i Tekhnika Eksperimenta, No. 2, 2005, pp. 49–60.Original Russian Text Copyright © 2005 by Artemiev, Belov, Brakhman, Zeldovich, Karelin, Kirichenko, Kozodaeva, Kuchenkov, Lyubimov, Mitin, Tsvetkova.     

Effect of the quasi-continuous equal-channel angular pressing on the structure and functional properties of Ti–Ni-based shape-memory alloys

The effect of severe plastic deformation by equal-channel angular pressing (ECAP) under normal and quasi-continuous regimes on the structure and the mechanical and functional properties of a Ti–50.2 at % Ni shape-memory alloy (SMA) has been studied. ECAP was carried out at an angle of intersection of channels of 120° in the normal regime with heating between passes at 450°C for 20 passes and in the quasi-continuous regime at the temperature of 400°C for three, five, and seven passes. The hot screw rolling with subsequent annealing at 750°C for 30 min and cooling in water was used as a control treatment (CT). A mixed submicrocrystalline and nanosubgrained structure was formed. The increase in the number of passes from three to seven led to a decrease in the average size of structural elements from 115 ± 5 to 103 ± 5 nm and to an increase in the fraction of grains/subgrains having a size less than 100 nm. After ECAP (seven passes) and post-deformation annealing at the temperature of 400°C for 1 h, a completely recoverable strain was 9.5%; after normal ECAP, 7.2%; after CT, 4.0%.     

Axisymmetric control valve for oil and gas equipment

Analysis of the design of pipeline control valves permits the development of a new system for regulation of the flow cross section in the valve.     

Function division in wear-resistant pipeline elements

A solution is proposed to the problem of lifetime in pipeline equipment. The principle is proposed for splitting up the functions of the pipeline components when the lines contain abrasive media. A theoretical basis is provided for the design of a sharp bend in a steel pipeline with the aim of improving the wear resistance. __________ Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 5, pp. 36–39, May, 2007.