M.D. Starostenkov
,
E. V.Kozlov
,
O. V. Andruhova
,
N. V. Lomskikh
,
N.M. Gurova and A. V. Borissov 1) General Physics Department
,
ASTU
,
Lenin St. 46
,
Barnaul
,
656099
,
Russia 2) Physics Department
,
TSABU
,
Solyanaya Sq.
,
2
,
Tomsk
,
634003
,
Russia
金属学报(英文版)
The kinetics of internal boundaries relaxation: antiphase domain boundaries and interphase boundaries-in the conditions of high-temperature annealing and the structure transformations are investigated in homophase and heterophase systems. Homophase systems look like ordered binary alloy and include antiphase domain boundaries of various orientation. Clear components border on ordered alloy in heterophase systems and two processes take place simultaneously here-disordering of binary alloy and solution in ordered phase of clear component. Computer experiment is realized in the sphere of temperatures close to the temperature of order-disorder phase transition in the limits of two-dimensional model of atom diffusion at the vacant knots of crystal lattics.
关键词:
computer simulation
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null
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null
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null
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M.D. Starostenkov
,
B. F. Demyanov
,
E.A. Kuklina and E. G. Sverdlova General Physics Department
,
Altai State Technical University
,
Lenin st 46
,
Barnaul
,
656099
,
Russia
金属学报(英文版)
Computer simulation of grain boundaries(GB) was carried out in Fe and ordered alloys NiAl and FeAl with B2 superlattice. In this work symmetrical tilt grain boundaries =5[100](012) and = 5[100](013) are studied. The atomic interaction has been described by Morse empirical central- force potentials.The atomic structure and energy of GB were investigated by means of construction of -surface using full atomic relaxation by method of molecular statics. It is shown that = 5 tilt GBs in Fe, Ni3Al and NiAl have several steady states. Comparison of our results with geometrical model of coincidence site lattice (CSL) was carried out. GBs in model CSL are unstable, the stabilization is achieved by additional displacement at some vector along the plane of defect.
关键词:
grain boundary
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null
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null
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null
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R. V. Safiullin
,
R.A. Vasin and F. U. Enikeev Institute for Metals Superplasticity Problems Khalturina
,
39
,
Ufa
,
450001
,
Russia
金属学报(英文版)
A method for determining the value of the strain rate sensitivity parameter m, of a thin sheet superplastic material, which is based on the results of constant gas pressure tests, has been developed in this paper. Unlike the conventional procedures the method involved provides the test conditions similar to those occurring during an industrial technological process. Such an approach enables one to estimate reliable the superplas- tic properties of the material under study. Theoretical analysis is based upon use of the standard equations of the membrane theory. The experimental investigations have been carried out for Ti-based alloy VT6 (Ti--6Al-4V). Theoretical predictions show satisfactory agreement with experimental data. The results obtained are compared with those measured by means of standard procedures (constant cross-head velocity experiments and load relaxation tests). It is shown that the use of specimens having reduced gage length (which is less than specimen's width) could lead to considerable errors in experimental estimation of the m value which, in its turn, leads to inaccurate calculating the technological parameters.
关键词:
superplasticity
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null
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null
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null
S. Fedosov Samara State Technical University
,
Galaktionovskaya 141
,
Samara 443010
,
Russia
金属学报(英文版)
"Thermo" computer program is described. It is intended for computation of thermal cycle parameters during surface pulse heating. For example, during laser processing, surface heating owing to grinding, etc. It gives rates of heating, cooling, as well as temperature gradients and cumulative exposure time as function of the CURRENT TEMPERATURE, with the peak temperature at the surface as variable parameter. The indicated parameters are calculated at a surface, close to a surface (at 0.01μm)and for the points at a depth of the body. Demo ver. of the software: http://www. sstu.samara.ru/physics/fedosov/thermo_d. zip
关键词:
heat transfer
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null
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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
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null
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