Dislocation substructure formed by irradiating iron with a low-energy high-current electron beam

Calculations were made of the time variation of the temperature in iron at different depths from a surface irradiated with a low-energy high-current electron beam. The mutual relationship betwen the changes in the dislocation and grain structures of the iron polycrystals and the maximum temperature reached during irradiation was traced. The variation of the microhardness in the surface layers of the irradiated iron was found to be nonmonotonic.V. D. Kuznetsov Siberian Physicotechnical Scientific-Research Institute, Tomsk State University. Institute of Power Electronics, Siberian Branch of the Russian Academy of Sciences. Physics Institute of Strength and Materials Science, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 42–47, May, 1993.     

Formation and development of laser physics at Tomsk University

The formation of the laser school in the Siberian Physical-Technical Institute at Tomsk State University is considered in historical perspective. The most important achievements and publications are discussed. The role of Siberian Conferences on Spectroscopy held regularly under the supervision of Prof. N.A. Prilezhaeva in the development of laser physics at Tomsk University and in the city of Tomsk is demonstrated. Tomsk State University; the V. D. Kuznetsov Siberian Physical-Technical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 4–13, August 1999.     

Microplastic deformation of polycrystalline and submicrocrystalline titanium during static and cyclic loading

A study is made of the laws governing the accumulation of microplastic strain during the static and cyclic loading of polycrystalline and submicrocrystalline titanium. It is shown that a change from the polycrystalline structure to the submicrocrystalline structure does not change the character of development of microplastic strain for either type of loading, but it does increase fatigue strength and fatigue limit. A correlation between the fatigue strength based on 10⁶ cycles and the macroscopic elastic limit was found to exist for both types of loading. Siberian Physico-Technical Institute (at Tomsk University), Institute of the Physics of Strength and Materials Science (in the Siberian Division of the Russian Academy of Sciences), and the Institute of the Physics of Promising Materials (at Ufa State University of Aeronautical Engineering). Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 41, No. 12, pp. 20–25, December, 1998.     

基于GaSe和GaSe0.7S0.3单晶的单脉冲CO2激光倍频器

描述了使用电感储能发生器和半导体转换开关泵浦的工作波长为10.6μm的高效CO2激光器。给出了激光泵浦的非线性晶体GaSe和GaSe0.7S0.3的二次谐波振荡的实验数据和理论估算结果。结果显示,GaSe晶体在输入能量为180mJ时,最大能量转换效率为0.38%,倍频激光的峰值功率为8 kW。     

Structure and mechanical and electrochemical properties of ultrafine-grained Ti

A study is conducted into the microstructure and physico-mechanical properties of ultrafine-grained titanium produced by severe plastic deformation using the method of equichannel angular pressing. The effects of thermal and mechanical treatment on these characteristics are investigated. The possibility of forming mechanical properties in titanium that compare well with those of highly doped titanium alloys is shown. Institute for Strength Physics and Materials Science; Siberian Physical-Technical Institute at Tomsk State University; Institute of Physics of Advanced Materials at UFA Aviation Technology University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 77–85, January, 2000.     

Effect of chromium on structure,strength, and plasticity of high-temperature intermetallide Ni3Al

The effect of chromium on structure, strength characteristics, plasticity, and failure principles in the polycrystalline intermetallide Ni₃Al, produced by self-propagating high-temperature synthesis, is studied over the temperature range 290–1270 K. It is shown that the effect of chromium depends upon which element (nickel or aluminum) it is introduced in place of, although failure of alloys with various chromium contents at all deformation temperatures remains intercrystallite in nature.V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk State University. Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 30–36, June, 1993.     

Anomalous mass transfer and phase and structural changes in α-Fe when acted upon with electron pulses

The phase composition and the defect structure of armco-iron irradiated with a relativistic electron beam is investigated using electron microscopy and x-ray structural analysis. Specimens with a chromium coating and without it were irradiated.Tomsk State University Architecture-Building Academy. Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 95–99, April, 1994.     

Phase transformations in disordered alloys of composition close to Fe3Pt

The phase transformations in disordered Fe₃Pt alloys with decrease in temperature are studied by x-ray structural analysis. Two simultaneous transformations are observed: an incomplete martensitic structural phase transition of the first kind and a -type intraphase (-phase) transformation. The martensitic transformation in Fe₃Pt alloy is preceded by the appearance of a singular pretransformational state in the -phase, in which the behavior of the fine-structure parameter differs from that in the initial state of this phase.Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences. Tomsk State Architectural and Building Academy. Translated from Izvestiya Vysshikh Uchebnykh Zavednii, Fizika, No. 4, pp. 83–88, April, 1994.     

Study of point defects for B2 structures with a ω-type martensitic phase

The molecular dynamics method has been used to study the effects of the inheritance from point defects in B2 structures having an -like martensitic transformation with different final reaction products. For order defects, antistructural atoms, and their simplest complexes it has been shown that in several cases the number of atoms in the defects increases sharply for martensite during the transition to austenite. Here the fraction of chemical energy accumulated by the defects grows. A certain type of defect in the B2 structure in martensite corresponds to the appearance of high-energy linear disordered chains in directions of the [111]_B2 type. This can play a substantial role in the determine the path of the reverse martensitic transformation.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 54–59, June, 1995.     

Effect of plastic deformation on phase transitions in a Ti50Ni47Fe3 alloy

The results of x-ray structural studies of the effect of previous plastic deformation by rolling on the occurrence of phase transitions in a TiNi(Fe) alloy are presented in the present work. The temperature dependences of the Bragg reflection intensities and half-widths and the dependence of the rhombic angle in the R phase with various degrees of deformation were obtained. Analysis of the results found gave the following rules. Plastic deformation substantially shifts the characteristic temperatures of the martensitic transitions (MT) R-B19′ and B19′-B19″, increases the temperature range of the transformation and can result in a “stepwise” transformation. It was observed that deformation weakly affects the temperature T_R for the B2-R transformation. Tomsk State Architecture and Construction Academy. V. D. Kuznetsov Siberian Physicotechical Institute at Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 11–20, July, 1996.     

The relaxation-element method in models of the plastic strain of structurally inhomogeneous materials

It is shown that it is possible to represent a continuous field of plastic strain with high gradients in local regions of a material by methods of the continual theory of defects. A practical method of constructing highly inhomogeneous fields of plastic strain in local regions of a solid under load is proposed, and the stress fields connected with them are determined. The method is used to propose a principle of a unique connection between the process of inelastic deformation and stress relaxation in local volumes of the material. This enables one to simulate the inhomogeneous fields of plastic strain and stresses connected with the external stress without discontinuities and singularities at the interfaces between the phases and crystallites.Institute of Physics of the Strength and Study of Materials, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 16–22, February, 1994.     

Effect of island number density of the surface evolution during molecular beam epitaxy

A combined simulation-analytical model is developed to describe the surface morphology evolution during molecular beam epitaxy. The effect of island number density on transition from one level growth to nultilevel growth has been studied. It is shown that decrease in the island number density (increase in the area per island) can involve such a transition even at fixed substrate temperature and growth rate. V.D. Kuznetsov Siberian Physicotechnical Institute, Tomsk University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 27–32, March, 1999.     

Influence of grain-boundary dynamics on shear and rotational deformation components in the creep of polycrystals

The as-a-whole motion of polycrystal grains with migrating and stationary boundaries is investigated during the creep of lead and lead-based alloys. It is shown that boundary migration promotes grain-boundary slip and fragmentation of regions along the boundaries, and that the effect is not related to differing orientations of the migrating and stationary boundaries. Migrating and stationary boundaries of equal slope were formed in aging alloys as a result of intermittent segregation and coalescence of phases. V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Tomsk Branch, Institute of Structural Macrokinetics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 40–45, June, 1998.     

Structural-phase analysis of sintered alloy WC-30% steel 110G13

Electron diffraction microscopy and x-ray diffraction analysis are used to study the phase composition and structure of hard alloy WC-steel 110G13 immediately after sintering and additional heat treatment. It is shown that quenching in water from 1370 K leads to disappearance of the excess phases and the formation of a less defective and more uniform structure.Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences. Tomsk State Architectural-Construction Academy. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 96–99, May, 1993.     

Effect of the hardened layer thickness of the formation of mesostructures during extension of surface hardened samples

We have made a systematic experimental study of the effect of the thickness of the surface hardened layer in planar samples of 65X13 steel on the geometric parameters of the quasiperiodic mesobustructures which are formed in the surface layer and the bulk of the sample during its plastic extension. The observed dependence of the dimensions of the fragments of mesosubstructure on the thickness of the surface hardened layer correlates well with theoretical calculations [1, 2] of the mechanical or thermal stress at the interface of two media in an external field. Institute of the Physics of Strength and Materials Science, Siberian Section, Russian Academy of Sciences. Tomsk Polytechnic University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 63–69, June, 1998.     

Structure studies on porous titanium nickelide made by high-temperature self-propagating synthesis

Structure studies are reported on martensite transformations in porous TiNi alloy made by high-temperatures self-propagating synthesis. The transformations occur over a large temperature range and are incomplete. The structure data are used in reconstructing the heat release during the transition, where it is shown that it is determined by the superposition of martensite transformations occurring locally at various temperatures. Tomsk State Architectural and Building Academy. Kuznetsov Siberian Technical Physics Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 20–24, January, 1997.     

Quasi-equlibrium description of acoustic emission in martensitic transformations

Acoustic emission is used to study martensitic transformations in metal systems within the framework of the quasiequilibrium theory. In this approach, the dissipative part in the balance equation of driving forces for the matertensitic transformation is represented as the sum of contributions from heat dissipation and “nonchemical” energy dissipation due to acoustic emission. The acoustic contribution is defined as dynamic relaxation which in its turn is related to the transformation kinetics. Examples of events responsible for the production of acoustic radiation are the “microexplosive” nucleation-collapse of martensite crystals, single acts of their stick-slip displacement, and plastic relaxation of elastic transformation stresses. Siberian Physicotechnical Institute at Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 72–79, October, 1999.     

Distortion deformations in the B2-R phase transition in titanium nickel alloys

Based on x-ray analysis, we have calculated the lattice distortions in Ti-Ni-Me (Me=Rh, Co, Fe) alloys during the B2-R phase transition. We find that, during the transition, the deformation decreases as the concentration of the alloying component increases in Ti-Ni-Rh and Ti-Ni-Co. No such correlation is observed in the Ti-Ni-Fe alloys. Tomsk State Architecture-Construction Academy. V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 95–100, February, 1997.     

Occultation of the plasma near the sun and the speed of the solar wind: Fluctuations in the frequency and phase of radio waves at two separated points

Radiotechnical and Electronics Institute, Academy of Sciences of the USSR. Siberian Physicotechnical Institute at Tomsk University. Translated from Izvestiya Vysshikh Uchebykh Zavedenii, Radiofizika, Vol. 32, No. 5, pp. 531–537, May, 1989.     

Fatigue failure mechanism of polycrystalline materials at the mesoscopic level

Systematic studies of the mesoscopic mechanisms of deformation of polycrystalline materials of lead and its alloys have been carried out under conditions of sign-alternating bending at room temperature. It has been shown that fatigue failure is due to the evolution of vortices of mesoscopic substructures. Multiple slip separated in adjacent grains is the basis for this kind of deformation. This causes extremely strong localization of the displacement in individual favorably oriented grains and self-organization of these grains in agreement with regular structural levels of deformation. In polycrystalline lead, the mesoscopic substructure has a block character, with each block containing several grains. The elements of such substructures are nucleated in stress mesoconcentrator zones which arise at the grain boundaries under conditions of intense grain boundary slippage. In the course of cycling they gradually propagate through the whole transverse cross section of the sample, which completes its failure. Alloying substantially changes the character of the mesoscopic substructures which are formed. We have considered the different types of vortex mesoscopic substructures and studied their connection with cyclical endurance of the alloy. Recommendations for increasing the fatigue endurance of plastic polycrystalline materials are given. Institute of the Physics of hardening and Materials Science, Siberian Section, Russian Academy of Sciences. V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 40–57, June, 1996.