Kinetics of mechanically induced segregation of chromium-nickel steels with regard for generation of point defects by glide dislocations under SPD [Kynetyka sehrehatsyy mechano-induced chromo-nykelevh steels with uch?tom generation tochechnh defects sliding dyslokatsyyamy in the process of IPD]
Varyuhyn V.N.,Donetsk Institute of Physical and Technical them |
Stefanovic L.I.,Donetsk Institute of Physical and Technical them |
Yurchenko V.,Donetsk Institute of Physical and Technical them |
Artmov A.,Donetsk Institute of Physical and Technical them |
And 3 more authors.
Metallofizika i Noveishie Tekhnologii
The process of mechanically induced separation caused by diffusion of point defects generated by glide dislocations during severe plastic deformation (SPD) is considered by the example of chromium-nickel steels. As established, the basic and determining source of point defects providing the effect of strain-induced segregation (SIS) is their generation by dislocations moving in the crystal. The evolution of dislocation density obeys the equation of continuity with sources and sinks. As shown, the formation of boundary segregations of alloying elements, namely, nickel, under SPD is connected with migration of the point defects of two types (vacancies and interstitial atoms) to the sinks and appeared as a result of asymmetry of these defects' flows. The reverse Kirkendall effect is the cause of this phenomenon. As found, the internal stress fields taken into account and caused by dislocation aggregations on boundaries of nanograins do not only accelerate the process of nickel segregation to the boundary, but, on the contrary, promote its partial desegregation depthward the nanograin. Source