Program and the Book of Abstracts (PDF) - Mrs-serbia.org.rs

Tenth Young Researchers Conference – Materials Science and Engineering
December 21-23, 2011, Hall 2, SASA, Knez Mihailova 35 & 36, Belgrade, Serbia
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Mössbauer analysis of the cold plastic deformation rate effect
on intermetallics dissolution in Fe-Ni alloys
V. Shabashov, V. Sagaradze, Kirill Kozlov, A. Litvinov
Institute of Metal Physics UB RAS, Yekaterinburg, Russia
Deformation rate as a critical parameter of the process of anomalously low-temperature
deformation-induced diffusion in metals is investigated for high rates έ = 10 2 …10 3 с -1 , for example,
at impact or impulse action. It is supposed, that in such cases the tension in structure reaches such
magnitudes which promotes the generation of interstitial positions that take part in low-temperature
nuclear mass transfer.
It was established that at low rates έ in the interval 10 -2 … 10 -1 с -1 , but at larger degrees ε =
4…7 of deformative influence under compression shear in Bridgman anvils the increase of rotation
rate in anvils from 0.3 to 1 rpm leads to large (about 30%) intensification of dissolution of
intermetallic particles Ni 3 Me (Me = Ti, Al, Zr, Si) in matrix of FCC Fe-Ni alloys. The method of
Mossbauer spectroscopy was used to determine the dissolution kinetics by the growth of effective
magnetic field on nuclei 57 Fe as a result of growth of nickel content in matrix at intermetallics
dissolution.
The kinetic curves of dissolution of particles with different morphology, sizes, crystal lattice
type, bonding forces and diffusion atom mobility were obtained. The rate influence is mostly
exhibited on the steep part of kinetic dependence of ΔC Ni on ε, when the rotation mode of
deformation dominates.
It is specified, that kinetics of deformation-induced nonequilibrium phase transitions is
controlled by the competitive development of alternative processes of phase dissolution and
extraction [1,2]. The increase of slope angle of kinetic dissolution curves happens mainly because
of the influence time shortening of alternative process of intermetallics extraction over vacancy
mechanism, and apparently because of the concentration growth of interstitial atoms which take part
in the nonequilibrium dissolution of intermetallics. Besides, it is shown that the increase of
deformation rate is accompanied by reduction of deformation incubation period ε 0 , necessary for the
preliminary particles splitting.
The obtained results have practical importance for the development of steels and alloys
strengthened with nanodimensional particles with the use of mechanical activation.
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