V. V. Roshchupkin

Liquid Gallium: Potential Uses as a Heat-Transfer Agent

This paper deals with potential uses of gallium, as well as the most important gallium-based alloys, as energy carriers in high-safety nuclear power plants. Experimental data are given on the thermophysical, electrophysical, chemical, acoustic, and other properties of gallium and its alloys.

THE DENSITY AND THERMAL EXPANSION OF EUTECTIC ALLOYS OF LEAD WITH BISMUTH AND LITHIUM IN CONDENSED STATE

The method of penetrating gamma-radiation is used to measure the density of lead-bismuth and lead-lithium eutectics in the condensed state in the range from room temperature to ~1250 K. The chemical composition of investigated eutectic alloys of Pb-Bi and Pb-Li systems is determined within ±0.2% by mass, and the lead content in these alloys turns out to be 44.6 and 99.3% by mass, respectively. The confidence error of the experimental results, which combines the systematic and random components, does not exceed 0.3% and 0.2% for the solid and liquid phases, respectively. The investigation results are compared with the available literature data on the density of eutectic alloys of lead with bismuth and lithium in the condensed state.

Experimental investigation of acoustic properties of titanium alloys in the temperature range of 20–1000°C

Titanium and titanium-based alloys, which are widely used in various sectors of the national economy, require deep and versatile investigations of their physico-mechanical properties in a wide temperature range. Numerous abnormal physical phenomena are observed in titanium-based alloys at high temperatures, especially in the region of polymorphic transformation. In particular, in addition to significant structural variations, which influence the strength properties of the final products, near such transformations the titanium alloys (especially with a fine structure) have a tendency to superplastic deformation, which is widely applied in modern technology. Among the physical characteristics, which provide extensive information about the structural and physico-mechanical properties of titanium alloys, are the temperature expansion and acoustic properties (in particular, the speed of ultrasound, information about the temperature dependence of which is unavailable for the majority of engineering materials), which allow the Young modulus for these materials to be calculated.

The Density of Liquid Sodium–Potassium Eutectic

The experimental investigations of the density of molten sodium–potassium alloys of eutectic composition, described in the literature, are briefly reviewed. This review is used to estimate the confidence error of the measurement results. The least squares method is used to simultaneously process the entire body of the experimental data on the density of the liquid Na–K eutectic. An approximating equation is derived for the temperature range from the melting point of the sodium–potassium eutectic to 1300 K. The mean-square error of the calculated values of the density of Na–K eutectic melt in the given temperature range is determined.

Features of the Damage and the Structural Changes in the Tungsten Surface Layer under the Pulsed Action of Laser Radiation,Ion and Plasma Fluxes

The degradation of a bilateral pressed tungsten surface layer by pulsed laser irradiation in the free-running mode (power density q = 105–5 × 106 W/cm2, pulse duration τ = 0.7 ms) and the Q-switched mode (q = 109–1010 W/cm2, τ = 80 ns) as well as under plasma beam irradiation in a plasma focus (PF) device (q = 108–1012 W/cm2, τ = 10–100 ns) has been investigated. The features of the degradation, erosion, and structural changes in the tungsten surface layer under different irradiation conditions have been determined. It has been shown that the use of PF devices in combination with laser equipment is promising for the simulation of the extreme radiation–thermal effects in materials that are typical of thermonuclear fusion devices with magnetic and inertial plasma confinement.

Experimental study of the Er308LSI steel acoustic properties

The experimental results on the acoustic properties (the ultrasound velocity and attenuation coefficient) and the relative thermal expansion of the Er308LSI steel within the temperature range of 20–1100°C are presented. Application of the dilatometer studies makes it possible to improve the accuracy of the experimental data on the acoustic properties and to calculate the temperature dependency of the steel density as well as of the Young modulus. The temperature dependencies and calculate the approximating equations for the investigated and the calculated properties of the steel are plotted.

Tribology of cutting by tools equipped with cBN-based PSHM

Mechanisms of the contact interaction between the cutting tool equipped with cBN-based PSHM and the material machined in the cutting zone have been considered. The influence of the thermobaric conditions of loading on the tool (cutting temperature and contact stresses) on the mechanisms has been discussed.

Investigation of the acoustic properties of zirconium

The results of an experimental study of the acoustic properties (speed and attenuation factor of ultrasound), the acoustic-emission properties, and the relative temperature expansion of zirconium in a temperature range of 20–1000°C are presented. The least-squares method was used to obtain approximating equations for the temperature dependences of the studied and calculated thermophysical properties of zirconium.

Investigation of the acoustic properties of cobalt

The results of the experimental investigation of the acoustic (ultrasound velocity and attenuation coefficient) and acoustic-emission properties, as well as of the relative thermal expansion of cobalt, within the temperature range of 20–1100°C are presented. By the mean square method, we obtain the approximating equations for the temperature dependencies of the investigated and the calculated thermophysical cobalt properties.

An investigation of the kinetics of structure transformations and phase transition in nickel using acoustic methods

Results are given of experimental investigation of the temperature dependence of the acoustic and acoustic-emission properties of nickel in the vicinity of magnetic phase transition (Curie point), as well as of their behavior in the process of annealing and quenching. The information content of these properties is demonstrated when investigating the evolution of nonequilibrium structures and phase transitions of metal materials.