材料期刊网

MATHEMATICAL SIMULATION OF HEAT AND MASS TRANSFER IN PULSED ARC WELDING BY MELTING ELECTRODE

O.I.Shpigunova , S. V. Shpigunov , Yu.N. Saraev (Institute of Strength Physics and Materials Science , Siberian Branch , Russian Academy of Sciences , Tom- sk , Russia)

金属学报(英文版)

In this paper the processes of melting and transfer of an electrode metal to the molten pool, hydrody- namics of molten pool in controlled pulsed arc welding in carbon dioxide have been investigated.The process of pulsed arc welding with systematic short - circuits of the arc gap is realized by adaptive algo- rithms of pulsed control over main energetic parameters of welding - arc current and voltage,arc heated efficiency,peak,short - circuiting current, which provide the dosage of energy for energy for melting and transfer of every for of an electrode metal, the control over fluidity of the weld pool. Physica and mathematical models describing such processes in CO2, origind software hare been developed.The re- sults of physical simulation and mathemaical modelling permit to determine the influence of energetic parameters of the process on the condition of the "power source-electrode-arc-molten pool" electrodynamic system at each moment of time.

关键词: pulse , null , null , null

Many-body Interatomic Potentials for Computer Simulation of Physical Processes in Metals and Alloys

V.M.Kuznetsov , G.E.Rudenskii , R.I.Kadyrov and P.Kaminskii (The Institute of Strength Physics and Material Science , Russian Academy of Sciences , Siberian Branch. Academicheskii av. 2/1 , 634048 Tomsk , Russia)

材料科学技术（英）

A model of binding forces in metals and alloys, based on the density functional theory and accounted effects of the many-body interactions, was proposed. The developed method can be easily applied for study of metals and alloys by the molecular dynamics simulation. The potentials of interatomic interactions have been found by the proposed method and applied for calculations of equation of state, elastic moduli and phonon dispersion in metals Ni, Al, alloys NiAl and Ni3Al. Results of the calculations are in good agreement with known experimental data both for pure metals and alloys.

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Realization of Superplastic State of Polycrystals under Grain-boundary Diffusion

Yu.R.Kolobov and I.V.Ratochka(Institute of Strength Physics and Materials Science , Siberian Branch of the Russian Academy of Sciences , 634055 , Tomsk , Russia)

材料科学技术（英）

Creep behaviour of Mo and Fe polycrystals has been studied for a wide range of Strain rates in the presence of grain-boundary diffusion flux of Ni. The role of the impurity grain-boundary diffusion and grain-boundary migratin in the realization of the superplastic strain of metals under these conditions is examined

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COMPUTER-AIDED DESIGN OF ADAPTIVE PULSED ARC WELDING OF ROOT WELDS BY MELTING ELECTRODE

Yu. N. Sarave , O. I.Shpigunova(Institute of Shength Physics and Materials Science , Siberian Branch , Russian Academy Of Sciences , Tom-sk , Russia)

金属学报(英文版)

The purpose of computer-aided design of new adaptive pulsed arc technologies of welding is: to de- sign optimum algorithms of pulsed control over main energy parameters of welding.It permits:to in- crease welding productivity, to stabilize the welding regime, to control weld formation,taking into ac- count its spatial position, to proveal specie strength of the welded and coatings. Computer- aided design reduces the time of development of new pulsed arc technology:provides the optimization of technological referes according to the operating conditions of welded joints,the prediction of the ser- vice life of the welds.The developed methodology of computer-aided design of advanced technologies, models, original software, adaptive algorithms of pulsed control, and spend equipment permits to regulate penetration,the weld shape, the sizes of heat - affected zone; to predict sired properties and quality of welded joints.

关键词: pulse , null , null , null

Calculation of Surface Energy of Metals and Alloys by theElectron Density Functional Method

VM.Kuznetsov , R.I.Kadyrov and G.E.Rudenskii (Institute of Strength Physics and Material Science , Russian Academy of Sciences , Siberian Branch.Academicheskii av. 2/1 , 634048 Tomsk , Russia)

材料科学技术（英）

The surface energy values of (100), (110), (111) surfaces in Ni. Al and ordered alloys NiAl and Ni3Al have been calculated within the framework of methodology based upon the electron density functional method. The results of calculations are in good agreement with the known for pure metals experimental data and in case of Ni3Al allop There is also a good agreement with the results obtained by calculation using the embedded atom method. The investigation has been carried out in this work to show that the surface energy σ of alloys can not be interpreted as an averaged concentration σ of pure metals. For NiAl, the obtained resulsts reveal considerable distinctions in anisotropy of a in comparison to the anisotropy of surface energy in pure matals.

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Spherical Asymmetric Solution for Point Defect

A. G.Ivanchin (Institute of Strength Physics and Materials Science , Siberian Branch of Russian Academy of Sciences , Tomsk , 634055 , Russia)

材料科学技术（英）

The article proves unsingleness of solution for the known elastic equilibrium equation for point defect. Another linear-independent solution. meeting the same boundary conditions as the classical one, has been found.

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RETAINED AUSTENITE IN LASER PROCESSED STEELS

S. Fedosov (Samara State Technical University , Galaktionovskaya 141 , Samara 443010 , Russia)

金属学报(英文版)

This paper Presents experimental data on effect of carbon concentration and laser processing regimes on retained austenite quantity. The data on retained austenite decomposition during subsequent temperings at various temperatures as well as after holding at room temperature during 3 years are given.Correla- tion between structural broadening of the X - ray lines of retained gamma - phase and the amount of the latter has been discovered.Mechanisms responsible for the increased quantity of the retained austen- ite in carbon and low alloyed steels after laser hardening are described.

关键词: retained austenite , null , null , null

Russia's Precious Metals Market: Condition and Prospects

KOTLYAR A. Yu.

贵金属

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The Work of NAHE on Promotion of Achievements in Hydrogen Energy in Russia and of Advantages of Using Platinoids in the Energy Sector

SHELISCH P. B. , RAMENSKY A. Yu. , BEKLEMISCHEVA O. A. , RAMENSKAYA E. A.

贵金属

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DEVELOPMENT OF EFFECTIVE TECHNOLOGICAL PROCESSES OF HIGH-STRENGTH STEEL WELDING

L.I.Mikhoduj (The E. O. Paton Electric Welding Institute , NAS of Ukraine , Kiev , Ukraine)

金属学报(英文版)

Composition and service properties of high - strength low-alloyed steels with 590-980 MPa yield strength,which find an application in Russia, Belorus,Ukraine and other countries of the former USSR in manufacture of welded structures of a powerful mining and transport machinery, are given. Electrodes and wires for main processes of arc welding of these steels have been devel- oped on the basis of a rational use of different systems of alloying (08KhN2GM,08KhNG2M, and also economical systems of type 10G25, ect. ). Main approaches to the technological provess- es of manufacture of structures of high - strength steels are formulated.They are mainly directed to the weakening of de offect of the factors which contribute to a delayed fracture of joints (diffusive hydrogen,unfavourable rates of cooling,level of residual stresses). When there are no stress concentrators (and at a low level of residual stresses) the welded joints of these steels have a good resistance to fatigue and brittle fractures.As a rule, they are prevented with the help of the known approaches.It is shown that in addition to them and due to a proper selection of conditions of welding the life of welded joints of the high - strength steels can be 1. 2 - 1. 4 times in- creased.

关键词: high-strength steel , null , null , null