Specific features of the strain-induced order-disorder phase transition and its mechanisms

In the present paper, the methods of x-ray diffractometry are used to investigate the influence of plastic deformation on the long-range atomic order in alloys with L1₂, L1₂(M), and L1₂(MM) superlattices. The influence of ordering energy, initial values of the long-range order parameter, and average sizes of antiphase domains on the specific features of the dependence of long-range order parameter on the strain degree is considered. It is demonstrated that the wetted strain-induced order-disorder phase transition occurs with rapid accumulation of antiphase boundaries that play an important role in the destruction of long-range atomic order.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 21–32, September, 2004.     

Effect of nonstoichiometry on the plastic behavior of Ni<Subscript>3</Subscript>Ge single crystals with the [001] orientation of the deformation axis

The effect of nonstoichiometry on the mechanical properties of Ni₃Ge alloy single crystals with the [001] orientation of the deformation axis has been investigated. It is shown that the limits of the temperature range of different stages shift to higher temperatures with an increase in nonstoichiometry. A change in the alloy composition only slightly affects the temperature dependence of the work hardening rate.     

Dislocation Creep of Single-Crystalline <Emphasis Type="Italic">L</Emphasis>1<Subscript>2</Subscript>-Superlattice Intermetallic Compounds

The creep phenomenon observed in ordered alloys and intermetallics with the L1₂-superlattice structure are considered. A mathematical model that accounts for the superlattice dislocation locking mechanisms at work during creep of the single crystals is constructed. Superposition of the thermal activation mechanisms of the superlattice dislocation motion and locking is shown to give rise to an anomalous temperature dependence of the creep rate. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 28–35, September, 2005.     

Dislocation dynamics and thermal hardening of alloys with L12 superlattice

We studied the effect of superdislocation velocities on thermal hardening of alloys with the L1₂ superlattice. We estimate the activation energy for self-stopping of dislocations due to changes in the elastic field of moving dislocations as compared with immobile dislocations. We calculate the velocity of a dislocation loop element, taking into account interactions with dislocations. We show that, because of deformation stress, superdislocations can move at nearly the speed of sound. This, in turn, can help reduce the activation energy for self-stopping processes of superdislocations by a factor of 1.3 to 5.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 57–61, February, 1996.     

Thermally activated deformation processes in monocrystals of an ordered Ni3Fe alloy

The temperature dependence of the flow stresses of monocrystals of an ordered Ni₃Fe alloy is studied. The mechanisms determining the temperature dependence are deduced from experiments on the variation of the deformation temperature and stress relaxation. A theoretical estimate is given for the contribution of the thermal component of the flow stresses, and is found to be in good agreement with experiment.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 86–91, 1979.     

Localized Plastic Deformation of Metal-Intermetallic Laminated Composites after Equal Channel Angular Pressing

Russian Physics Journal - The paper presents mathematical simulation of localized plastic deformation of metal-intermetallic laminated composites after equal channel angular pressing. Deformation...     

Modeling of Plastic Flow Localization and Crack Formation in Dynamic Channel Angular Pressing

Russian Physics Journal - The paper studies the phenomenon of localized-deformation macrobands and crack formation in metal alloys under dynamic channel-angular pressing. The numerical calculations...     

Thermodynamic Analysis of the Contributions from Dislocational Substructures to Deformation Processes in Single Crystals of Nickel

A thermodynamic analysis of deformation mechanisms is performed, based on an experimental study of dislocational substructures that form as a result of the deformation of single crystals of nickel at room temperature. It is shown that in single crystals of pure nickel, strain produces a mainly thermal effect. The most important factors responsible for the accumulation of internal energy are elastic and dislocational components.     

Ordering kinetics in the alloy Au4Cr

The kinetics of the appearance of long-range order and the growth of antiphase domains (APD) in the alloy Au₄Cr with the superstructure Dl_a in the ordered state are studied by x-ray diffraction methods. The features of the incubation period are investigated. It is established that ordering in the alloy Au₄Cr occurs heterogeneously with the nucleation of well-ordered particles.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 98–105, December, 1991.