The Finkelshtain-Rosin effect in deformed f.c.c. steels

Experimental data on effect of plastic deformation on the carbon internal f riction peak in austenitic steels (Finkelshtain-Rosin peak) were analysed a nd it was shown that the general regularity is that peak height increases w hereas the peak temperature is rather stable, or decreases. To explain this effect the computer simulation of temperature dependence of internal frict ion was performed in a model crystal without and with a screw dislocation t aking into account long-range C-C and C-Ni interaction and C-dislocation in teraction. The last one was calculated by the so-called 'hybrid' method. It was shown that the elastic field around a dislocation enhances the asymmet ry of metal atom displacements around interstitial atoms and, thus, increas es the height of the peak. On the other hand, the weak energy for carbon-di slocation interaction in the f.c.c. lattice does not lend to significant ch anges in carbon atom energies. Thus, the corresponding value of the activat ion energy for carbon atom 'diffusion under stress' remains nearly the same as for the nondeformed alloy. For the same reason, there is no additional internal peak in austenite, in contrast with the Snoek-Koster peak in ferri te. (C) 2000 Elsevier Science S.A. All rights reserved.