Effect of rapid thermocyclic tempering on substructure,phase composition,and the initiation of fracture in a martensitic steel

The method of electron microscopy is used to study the fine structure of martensitic steel 17Kh4N2M2VF when subjected to rapid thermocyclic tempering. It is found that substructural and phase transformations take place in martensite due to repeated rapid temperature changes within the range 20–700°C. The phase transformations involve the decomposition of cementite and residual austenite and the formation of special carbides. The substructural changes are connected with fragmentation of the material. The density of high-angle fragment boundaries increases near the specimen surface along with scalar and excess dislocation density. The phase structural transformations entail the formation of long-range stress fields, the local relaxation of which leads to the development of microcracks and fracture of the material.Tomsk State Architectural-Construction Academy. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 36–42, February, 1994.     

Dissipation of energy in the contact of materials having shape memory

Problems of dissipation of energy in the contact of bodies made of titanium nickelide are studied by the mechanocycling method. Under normal loading or joint action of normal and shearing forces the dissipation of energy ΔW, determined from the hysteresis loop area enclosed by the dependences pressure q—approach δ and shearing force τ-shift Δ, is several times higher than that of traditional materials, and the dependence τ-Δ is nonmonotonous in character and has some extreme points. The peculiarities in the formation of hysteresis loops are established. The obtained results are explained in the context of thermoelastic martensite transformations and the theory of contact interaction. V. D. Kuznetsov Siberian Physical-Technical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 83–87, March, 1999.     

Computer simulation of deformation of two-component compacts under liquid-phase sintering

A model is proposed for predicting the deformation of two-component compacts under diffusion accompanied by phase transformations. The model is based on the movable cellular automata method. Dilatancy effects of a Cu−Al powder mixture under liquid phase sintering are described by means of computer simulations. Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 69–74, March, 1999.     

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.     

Potentials reducing the one-dimensional Schrödinger equation to the Mathieu equation

Potentials and the corresponding transformations reducing the Schrödinger equation to the Mathieu equation are presented. Solutions for Schrödinger equation corresponding to the given potentials are considered as well as the allowed energy values.Tomsk State Pedagogical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 72–75, June, 1994.     

Algebra of quantum transformation of standard and extended BRST-symmetry

Using the Lagrangian statement for quantization of general gauge theories (in the absence of anomalies), we introduce quantum transformations for standard and extended BRST-symmetry in the form of symmetry transformations of renormalized effective actions and study their algebraic properties, as well as the properties of the operators for the corresponding Noetherian charges. Tomsk State Pedagogical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 37–41, September, 1997.     

Laws of substructural and phase transformations in the plastic deformation of martensitic steel

Substructural and phase transformations in the course of plastic deformation in tempered 34KhN3MFA steel are considered. A relation is established between the type of substructure and the phase state of carbon. A direct relation is established between the carbon content in the solid solution and the crystal-lattice distortion. The carbon concentration at dislocations and fragment boundaries is determined.Tomsk State Architectural and Building Academy. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 76–82, April, 1994.     

Degenerate Structure of Transformation Twins and Estimation of Dislocation Density in Martensite Crystals

Physics of the Solid State - In the dynamic theory of martensitic transformations, the wave mechanism of controlling martensite crystal growth is determined by the superposition of wave beams of...     

Semibounded symmetry operator transformation of nonrelativistic free-particle coherent states

Coherent-state systems are considered that are obtained by applying symmetry operators to free-particle coherent states. Existence and uniqueness are proved for measures providing the expansion of a unit operator in terms of those states. Integral equations are given for determining the corresponding measures. Tomsk State University and Tomsk State Pedagogic University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 42, No. 2, pp. 12–18, February, 1999.     

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.     

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.     

Darboux transformation of the coherent states of a nonrelativistic free particle

Various systems of soliton-potential coherent states have been derived. Measures are found that realize the expansion of a unit operator in terms of projectors on these states. Two different realizations of Hilbert state space are constructed as functions holomorphic throughout the complex plane and with a certain constraint on their increase. Tomsk State University and Tomsk State Pedagogic University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 42, No. 2, pp. 19–25, February, 1999.     

Possibility of constructing a gauge-invariant quantum formulation for nongauge classical theory

A general method is proposed for the construction of a gauge-invariant canonical quantum formulation for the gauge-invariant classical theory that depends on the set of parameters. The conditions for closure of the algebra of operators, which generate quantum gauge transformations, entails constraints on the parameters of the theory. The approach described is demonstrated by the example of a closed bosonic string, interacting with a background tachyonic field. The condition of a mass shell for the tachyon is reproduced within the framework of the proposed canonical formulation. Tomsk State Pedagogical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 18–24, June, 1997.     

Special features of polytype transformations under changing external shear stress and temperature

Within the generalized axial finite-dimensional Ising model, possible model and experimental non-equilibrium polytype 3C-2H and 9R-3C transformations and twinning of the fcc-lattice of close-packed model crystals are considered. These transformations are realized in a great number of metals as well as cobalt, iron, and copper-base alloys and observed on variation of both the applied load and the temperature. The structure transformations simulated in the model may involve a number of multilayer metastable structures. Hysteresis phenomena found under variations of the external stress and temperature and their behavior in response to long-range interactions corresponding to atomic interactions in the fcc lattice in ten coordination spheres and in many-body interaction responsible for the stability of the 4H structure are considered. Factors accounting for the formation of metastable states and hysteresis effects are analyzed. It is shown that the crystal form may undergo a non-monotonic change as the applied load and temperature are varied. Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 80–86, September 1999.     

Nontrivial conformally steckel metrics in einstein spaces

All isotropic conformally Steckel metrics are derived that satisfy the Einstein vacuum equations containing a Λ term and do not reduce to the purely Steckel type. The metrics allow the integration of the Hamilton-Jacobi equation for a massless particle by complete variable separation. Tomsk State Pedagogic University. Tomsk State University. High-Current Electronics Institute, Siberian Division, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 74–78, October, 1997.     

Low-temperature tempering kinetics of hardened steel 38KhN3MFA

Diffraction electron microscopy was used in a study of the decay kinetics of the α-iron solid solution and the growth kinetics of cementite particles in steel 38KhN3MFA after tempering at 200–550°C. Growth equations are written for cementite particles formed in lamellar high-temperature martensite crystals. Tomsk Structural Engineering Institute, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 39–44, February, 1993.     

Some properties of higher-order Darboux transformations

We introduce the operator of the Darboux transformation of order n as an nth-order differential operator transforming the solution of the one-dimensional Schrödinger equation with a given potential into the solution corresponding to a different potential. For n=1 we obtain the usual Darboux transformation. It is shown that when n1 this transformation can always be represented as a product of n first-order Darboux transformations. We discuss the relationship between higher-order Darboux transformations and the supersymmetric approach to quantum mechanics and also the algebra of the dynamical symmetry of the system.Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 3–8, July, 1995.     

Isotropic Steklov-conformal metrics of plane-conformal spaces

An explicit form is found for metrics that allow integration of geodesic equations for massless particles in plane-conformal spaces by complete separation of the variables in the Hamilton-Jacobi equations. Tomsk University and Tomsk State Pedagogical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 92–96, November, 1998.     

Cosmological solution of the Einstein—Weyl equation

The accurate integration of the Einstein—Weyl field equations is considered for the case when the spinor field depends only on the time, while the metric specifies a uniform space—time of type I in the Bianci classification, i.e., a particular case of a Steckel space of type (3.0). Tomsk State Pedagogical University. Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 69–78, November, 1998.     

CEMS of Sb+ implanted stainless steels

Martensitic transformations have been analysed in a series of antimony implanted austenitic stainless steels using CEMS. The implanted samples contain about 70 vols martensite, which is considerably more than can be formed conventionally by plastic deformation or cooling below the martensite start temperature. CEM spectra from implantation induced martensite and from martensite formed in conventional processes are virtually identical. In both cases the hyperfine field is ≈ 25T.