PHENOMENOLOGICAL THERMODYNAMICS OF SUPERHIGH-ENERGY ELECTROIMPULSES IN METAL MELTS

© Dmitry I. Korneev

© Oleg O. Fejgin

Contact to authors: tor@3s.kharkov.ua

The problem of making new steels, alloys, solid solutions and intermetallic compounds, is closely bound to search of effective physical methods of guidance interphasic transitions. One of the most innovational expedients of perspective metal materials formation on a basis of less-dendrite materials is electro current pulsing processing /ECPP/ on a procedure of academician D. I. Korneev [1, 2]. ECPP is characterized by passage of a series of superhigh-energy electroimpulses /SHEEI/ through hardening metal and it is accompanied by a series of not trivial physical processes. The analysis of these processes has allowed revealing their phenomenological thermodynamics, the bound with the kinetic evolutions of thermo-gradients and oscillation of thermo-wave packages.

In the present publication, consecutive thermodynamic stages of development of ECPP-effect in a context before the offered theory of quasi-plasmon formations /QPF/ in metals [3] are considered some. In a basis of QPF-theory representations is incipient at super-power discharges in the dense fluid conducting medium such as fused metal lay. Subsequent dissipation of similar metastable plasmoids is accompanied magneto hydrodynamic currents and thermo-gradients chaotic redistribution.

Let us consider initial ECPP-stage, described by passage initial ECPP through fluid of metal melts. Development of leader-streamer initiating channels gives in occurrence of some set of volumetric no equilibrium streams of heat. At the second stage, there is a thermo-gradients formation at a partial dissipation of energy during a dispersion of charge carriers in homogeneities of medium and phase boundaries. The third stage contains secondary processes of inertia thermo-gradients essential influence. The final stage is characterized by the whole spectrum of relaxation reactions responses on a blanket phone of structural reorganization [4].

Non-stationary three-dimensional process of distribution thermo-wave from the treelike current cords making the channel of the electro discharge, in requirements of a nonlinear thermal conduction of medium, may be well enough submitted by the equation [5]:

dT/dt = d (K/pc dT/dx)/dx + d (K/pc dT/dy) dy + d (K/pc dT/dz)/dz + Q(x, y, z, t, T) - Q*(x, y, z, t, T), (1)

Where T -temperature; t -time; K -coefficient; ð -density of medium; c -specific heat capacity; Q, Q* -radians and sinks of thermo-waves. The analysis (1) shows, that despite of neglect structural sensitivity of quantities c, p, and K, local integrated solutions of a view

T(x, t) = const Ö (pc/Kt) ∫T (l)/exp [pc (x-l)²/4Kt] dl, (2)

Have attributes of self-similarity on the allocated site of localization l and transformations-invariant of squeezing and a tension. The energy balance of the above-described processes will be determined by the following equality:

I (E) exp (E/kT) =S E (i) +S E (j) +S E (n), (3)

Where I (E) -spectral intensity of a stream of charge carriers; kT -thermodynamic temperature; E (i) -energy of a dispersion on a -types of recombination centers; E (j) -interacting energy; E (n) -energy oozed on c –kind of flaws.

In turn, for analytical solutions for thermal waves we shall search as:

T(x, y, z, t) = T [(x - vt), (y - vt), (z - vt)]. (4)

Thus, it is possible to count, that hardening medium is characterized by non-stationary fields of no equilibrium radiant thermal energy. Thus if oscillation of heat occurs in a wave mode, radiating from channels ECPP-effect of their further distribution will be redistribution of diffusion cross-section and localization of thermal in homogeneities in boundaries of the dissipative metastable substructures. Their properties can be predetermined by studying solutions of the equations (2) and (4).

Evolution of the metastable thermodynamic structures implemented in course of ECPP is necessary to note, that, is accompanied by a series of depression reactions in melts phases:

{T (i)} + E (pl) +S A (i) ® {T (j)} +S B (j), (5)

Here {T (i)}, {T (j)} –undular wave packages; E (pl) -energy of an integrated fluency of SHEEI from the equation (3); A (i), B (j) -the generalized geometrical factors.

The variations analysis of relation (5) shows, that development dynamics of ECPP-effects contains transitions from non-stationary quasi-closed dissipative structures to unclosed thermodynamic systems with structures of radiant and sinks of heat. The most difficult for the analysis the material contains in spatial topology of plasma cords of a crown of the discharge and central current channels. Here it is necessary to take into account that the symmetric excitation of locally isolated gradients may give in formation of thermal structures aspiring to some blanket centre.

Surveyed thermodynamic ECPP-effects confirm presence enough the composite non-stationary dissipative reactions giving in occurrence of cyclic processes of degree change of phases order. Similar processes by virtue of the self-similarity are of interest as self-maintained objects of examinations in the field of a synergetic and no equilibrium thermodynamics.

REFERENCES

1. Korneev D.I. Examination of influence of parameters of electro current pulsing processing on change of operational properties of welded joints // Coll. of Scientific Works of UAS. - 2000. – No 1. - P. 54 - 61.
2. Korneev D.I. Influence of parameters of electro current pulsing processing on structure and mechanical properties of welded joints steels // ibid. - P. 62 - 72.
3. Korneev D.I., Fejgin O.O. Model physical mechanisms of high-energy action on a melt of metal // ibid. - P. 52 - 53.
4. Fejgin O.O. Action of high-energy electroimpulses on metal melts
5. Korneev D.I., Fejgin O.O. Paradoxical physics of super-power impulsing discharges

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