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

In the dynamic theory of martensitic transformations, the wave mechanism of controlling martensite crystal growth is determined by the superposition of wave beams of quasi-longitudinal (or longitudinal) waves carrying the "tensile-compression" deformation in the orthogonal directions. The wave beam formation is considered to be a result of the formation of excited (vibrational) states. The existence of transformation twins is interpreted as a result of a matched propagation with respect to long-wave (l waves) and short-wave (s waves) shifts. The matching condition is analyzed for the gamma-alpha martensitic transformation in iron-base alloys. It is shown for the first time that the transition to a degenerate twin structure with the allowance for the medium discreteness enables one to estimate the dislocation density in crystals with habit {557}, which agrees with that observed experimentally

Dynamic Scenarios of the Formation of Martensite with the {110} Habits in the Ni50Mn50 Alloy

Martensitic transformation B2–L10 in the ordered alloy Ni50Mn50, which occurs at comparatively high temperatures (980–920 K), is discussed with the use of dynamic concepts of the wave control of the threshold deformation. The proximity of the observed orientations of martensite-crystal habits (and of twin boundaries) to the planes of the {110} family makes it possible to use the longitudinal waves along the axes 〈001〉 (in the basis of the initial phase) as the driving factors. It is shown that at temperatures of the onset of the transformation there is a satisfactory correspondence between the calculated and experimental data on the tetragonality of martensite and on the volume effect. The opportunity of different dynamic scenarios of the formation of the final phase is noted, namely, of separate crystals; layered structures, in which the crystals of martensite with the identical orientation relationships alternate with the untransformed regions of austenite; and packets of pairwise-twinned crystals. Examples are given of morpho-types corresponding to these scenarios. © 2019, Pleiades Publishing, Ltd

The formation of martensite crystals with a degenerate structure of transformation twins

The dynamic theory of martensitic transformation explains the phenomenon of initiation of the fine structure of transformation twins as a result of the coordinated action of relatively long-wave displacements (ℓ-waves) with more short-wave displacements (s-waves). Being a part of a controlling wave process, ℓ-waves provide habit formation, whereas s-waves play the leading part in initiation of the main component of twin structure (TS). It was shown that the dynamic theory allows one to consider the degenerate TS (DTS) formation as a particular case of TS when the twin component volume is converted to zero. In this work the case of DTS is discussed by the example of crystals with habits {110}. The peculiarity of this variant consists in the fact that in order to describe the morphology of transformation it is enough to only consider longitudinal waves running along axes <100> as a part of the controlling wave process. In particular, habit (101) may be matched with a pair of ℓ-waves with velocities along [100] and [001] and a pair of s-waves with velocities along [100] and [010]. At the same time, condition d s = λ s / 4, where λ s is the wavelength of s-waves, and d s is a transversal (in directions [100] and [010]) size of the initial exited (oscillatory) s-ℓ-cell with longitudinal size d s << d ℓ < λ ℓ / 2, conforms to DTS formation. For martensite transformations fcc-bct, bcc-fct, fcc-fct, the transition to finishing deformations and the connection of the values of tetragonality of martensite and volume effect with one of characteristic main values of deformation tensor are discussed. © 2018, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

The formation of martensite crystals with a degenerate structure of transformation twins

The dynamic theory of martensitic transformation explains the phenomenon of initiation of the fine structure of transformation twins as a result of the coordinated action of relatively long-wave displacements (ℓ-waves) with more short-wave displacements (s-waves). Being a part of a controlling wave process, ℓ-waves provide habit formation, whereas s-waves play the leading part in initiation of the main component of twin structure (TS). It was shown that the dynamic theory allows one to consider the degenerate TS (DTS) formation as a particular case of TS when the twin component volume is converted to zero. In this work the case of DTS is discussed by the example of crystals with habits {110}. The peculiarity of this variant consists in the fact that in order to describe the morphology of transformation it is enough to only consider longitudinal waves running along axes <100> as a part of the controlling wave process. In particular, habit (101) may be matched with a pair of ℓ-waves with velocities along [100] and [001] and a pair of s-waves with velocities along [100] and [010]. At the same time, condition d s = λ s / 4, where λ s is the wavelength of s-waves, and d s is a transversal (in directions [100] and [010]) size of the initial exited (oscillatory) s-ℓ-cell with longitudinal size d s << d ℓ < λ ℓ / 2, conforms to DTS formation. For martensite transformations fcc-bct, bcc-fct, fcc-fct, the transition to finishing deformations and the connection of the values of tetragonality of martensite and volume effect with one of characteristic main values of deformation tensor are discussed. © 2018, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

The degenerate structure of transformation twins and the monocrystallinity of part of the thin-plate martensite initiated by a strong magnetic field

In the dynamic theory, the formation of twin martensite crystals is the result of a coordinated propagation of relatively long-wave (l -waves) and short-wave (s-waves) displacements. The matching condition is analyzed for the γ–α martensitic transformation in iron-based alloys, taking into account the quasi-longitudinalness of the l -wave carrying compression deformation. It has been shown for the first time that the previously established single-crystal effect of part of the crystals of thin-plate martensite, which arises upon cooling under the action of a strong magnetic field, can naturally be interpreted as a consequence of the formation of a degenerate structure of transformation twins. © 2020, Allerton Press, Inc

The formation of martensite crystals with a degenerate structure of transformation twins

The dynamic theory of martensitic transformation explains the phenomenon of initiation of the fine structure of transformation twins as a result of the coordinated action of relatively long-wave displacements (ℓ-waves) with more short-wave displacements (s-waves). Being a part of a controlling wave process, ℓ-waves provide habit formation, whereas s-waves play the leading part in initiation of the main component of twin structure (TS). It was shown that the dynamic theory allows one to consider the degenerate TS (DTS) formation as a particular case of TS when the twin component volume is converted to zero. In this work the case of DTS is discussed by the example of crystals with habits {110}. The peculiarity of this variant consists in the fact that in order to describe the morphology of transformation it is enough to only consider longitudinal waves running along axes <100> as a part of the controlling wave process. In particular, habit (101) may be matched with a pair of ℓ-waves with velocities along [100] and [001] and a pair of s-waves with velocities along [100] and [010]. At the same time, condition d s = λ s / 4, where λ s is the wavelength of s-waves, and d s is a transversal (in directions [100] and [010]) size of the initial exited (oscillatory) s-ℓ-cell with longitudinal size d s << d ℓ < λ ℓ / 2, conforms to DTS formation. For martensite transformations fcc-bct, bcc-fct, fcc-fct, the transition to finishing deformations and the connection of the values of tetragonality of martensite and volume effect with one of characteristic main values of deformation tensor are discussed. © 2018, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

The formation of martensite crystals with a degenerate structure of transformation twins

The dynamic theory of martensitic transformation explains the phenomenon of initiation of the fine structure of transformation twins as a result of the coordinated action of relatively long-wave displacements (ℓ-waves) with more short-wave displacements (s-waves). Being a part of a controlling wave process, ℓ-waves provide habit formation, whereas s-waves play the leading part in initiation of the main component of twin structure (TS). It was shown that the dynamic theory allows one to consider the degenerate TS (DTS) formation as a particular case of TS when the twin component volume is converted to zero. In this work the case of DTS is discussed by the example of crystals with habits {110}. The peculiarity of this variant consists in the fact that in order to describe the morphology of transformation it is enough to only consider longitudinal waves running along axes <100> as a part of the controlling wave process. In particular, habit (101) may be matched with a pair of ℓ-waves with velocities along [100] and [001] and a pair of s-waves with velocities along [100] and [010]. At the same time, condition d s = λ s / 4, where λ s is the wavelength of s-waves, and d s is a transversal (in directions [100] and [010]) size of the initial exited (oscillatory) s-ℓ-cell with longitudinal size d s << d ℓ < λ ℓ / 2, conforms to DTS formation. For martensite transformations fcc-bct, bcc-fct, fcc-fct, the transition to finishing deformations and the connection of the values of tetragonality of martensite and volume effect with one of characteristic main values of deformation tensor are discussed. © 2018, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

On the mechanisms of bismuth transmutation in a BiPb melt under the influence of nanosecond electromagnetic pulses

The effect of nanosecond electromagnetic pulses on the bismuth-lead melt allowed us to establish an increase in the proportion of lead due to the transformation of Bi -> Pb. An electronic capture was assumed as a probable transition mechanism. The presence of isotopes Bi210m, Bi208, Bi207 in the initial samples was assumed too. However, the capture of an electron is characteristic only for Bi208, Bi207. Natural bismuth is represented by the isotope Bi209. Therefore, it is necessary to consider the transformations of this isotope. It is assumed that the leading role in the transformation is played by the vapor phase. It is shown that in the presence of water vapor, an increase in the melt mass Delta m > 0 is possible both due to the interaction of Bi209 nuclei with "quasineutrons" (including "neutroids" of Santilli and "hydrino" of Mills) as well as with "pseudoprotons" and "protoids" (the last two terms refer to the bound states of a proton with two electrons). The sizes of the bound states are substantially smaller than the Bohr radius R. The increment of the lead fraction occurs due to the isotope Pb210. On the contrary, the intensification of alpha-decays under conditions of electromagnetic pulsed exposure should be accompanied by an increase in the fraction of lead due to the Pb206 isotope and a decrease in the mass of the melt. Under the conditions of isolation of the melt from water vapor, the melt mass loss Delta m 0 расплава, как за счет взаимодействия ядер Bi209 с «квазинейтронами» (включая «нейтроиды» Сантилли и «гидрино» Миллса), так и с «псевдопротонами» и «протоидами» (два последних термина относятся к связанным состояниям протона с двумя электронами). Размеры cвязанных состояний существенно меньше боровского радиуса RB≈5 ∙10−11 м. Приращение доли свинца происходит за счет изотопа Pb210. Напротив, интенсификация α-распадов в условиях электромагнитного импульсного воздействия должна сопровождаться приращением доли свинца за счет изотопа Pb206 и снижением массы расплава. В условиях изоляции расплава от водяного пара можно ожидать убыли массы расплава Δm<0 за счет α-излучения ядер Bi209 с последующим улетучиванием гелия и накоплением изотопа Tl205. Распад ядер обусловлен интенсификацией туннельного эффекта. При этом не следует ожидать увеличения доли свинца за счет изотопа Pb207. Важно, что оценка значений Δm~0.1 г для реальных экспериментов указывает на возможность ее надежного измерения. В заключение кратко обсуждаются перспективы исследований

The role of the electronic current component in the formation of a quasi-molecular state leading to the synthesis of elements

It was previously shown that in the process of plasma water electrolysis, a synthesis of chemical elements is observed indicating the existence of low-energy nuclear fusion reactions. In the traditional consideration, for guaranteed fusion of nuclei, their approach to a distance of the order of the nucleus size Rn ~10−15 m is required. An additional possibility is to use electromagnetic interaction to achieve an intermediate quasimolecular state with a critical internuclear distance of Rc~10−13 m, which is smaller than Bohr radius RB ≈ 5 ∙10−11 m, but larger Rn. When Rc is reached, the process of attraction of the nuclei becomes possible due to the exchange of virtual electron-positron pairs, the efficiency of which increases with the approach of the nuclei. Since in the framework of the hadronic mechanics of Santilli, the π0-meson is interpreted as a result of the contact interaction of an electron and a positron, the stage of approach of the nuclei from Rс to Rn due to the exchange of quasipositroniums can be considered as an extension of the action of the Yukawa mechanism on scales up to Rс. Thus, the approach of nuclei to Rc plays a key role in the implementation of nuclear fusion. A similar approach is possible if a high electron density arises between the nuclei in the process of inelastic collision of ions (atoms). In the model of an intermediate quasimolecular state, an increase in the internuclear density of electrons is considered to be a consequence of the formation of pair Bose-type electronic states arising from the contact interaction (attraction) of electrons at the femt scale as shown in hadron mechanics. Therefore, the electronic component of the current during the electrolysis of solutions should contribute to the synthesis of elements by initiating the formation of Bose electron pairs in tunable shells of ions (atoms). This conclusion is confirmed by estimates of the transparency coefficient for electron tunneling through the Coulomb barrier. The transparency coefficient for the tunneling of hydrogen nuclei in muon catalysis is estimated. The possibility of the occurrence of simple nuclear reactions during the interaction of the initial nuclei with quasineutrons is noted. © 2020, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved