Mass transfer in iron and nickel stimulated by pulsed laser radiation is studied by the radioactive isotope method. New experimental results are obtained and an analysis in terms of kinetic equat.ions is given. It is shown: (a) exposure of the metal surface to high intensity pulsed laser radiation leads to an accelerated atomic migration into the sample; (b) an effective retardation, the value of which depends upon the presence of crystalline defects in metals has an esaential influence on the atomic migration rate stimulated by the laser; (c) multiple laser loading results in a concentration maximum formed inside the sample, the depth displacement of which depends upon the energy of light flux and the number of pulsed loadings.
Polymorphic transformations (PT) f.c.c. + h.c.p. in Co are investigated on the basis of Born's thermodynamic theory. The spontaneous deformation u2p is the P T parameter; the volume exchange w is the additional variable. The P T problem is reduced to Landau's theory with the variable uZ3. The elastic moduli in this case are: (Cll -GIl2) + 0 and C,,(T) = -C,,(T) in the point T = Too (Too is the point of the instability). The mibxima of the thermal expansion coefficient (TEC) and the elastic moduli as functions of T are calculated in the case of the first-order PT.TEC anomalies are calculated by the method of near the orientational phase transition (OPT) point in Co and Ni. TEC is measured by the method of the continual T-exchange. Anomalies of the TEC are found in the region of the P T in Co and near OPT in Co and Ni (near 500 K). The TEC quantities are in accord with the theoretical estimations. The TEC peak in the P T region permits to find the parameters of anharmonicity.
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