THE DISLOCATION-ENHANCED SNOEK PEAK IN Fe-C ALLOYS

Abstract

Some experimental conditions which generate the dislocation-enhanced Snoek peak in Fe-C alloys are presented. The results indicate that the movement of non-screw dislocation segments is involved in the relaxation mechanism. The results are consistent with the movement of non-screw dislocations in a medium with a viscosity proportional to the Snoek relaxation time, or alternatively, to a limiting case of the generation of kinkpairs on non-screw dislocation, i.e. a carbon Snoek-Köster relaxation

Magnetic after-effect study of dislocation relaxation in Fe-based alloys

“…Most intriguing temperature region is around 200 K -300 K since, due to the presence of carbon and nitrogen Snoek relaxation processes (290 K and 320 K measured at about 1 Hz [8]) it has been argued that the γ-relaxation is almost fully suppressed [19]. Still, most of the cold-worked iron alloys and steels show the existence of complex dislocationrelated relaxation processes in the temperature region around 200 K -300 K [20], which are not fully understood [21].…”

Mechanical Spectroscopy Of Bearing Steel

“…The interactions between dislocations and shortrange mobile carbon atoms can be assessed by the dislocationenhanced Snoek peak in iron-based alloys [11,16,[19][20][21][22][23][24]. It is important to note that the dislocation-enhanced Snoek peak is observed in ultra-high purity and technical purity Fe-C alloys containing very low concentration of carbon atoms [16,20,21,23]. Thus, not surprisingly the dislocation-enhanced Snoek peak is also observed in a commercial bake-hardening steel [24].…”

“…For example, mobile dislocation segments dragging along with them the Cottrell cloud of long-range mobile foreign interstitial atoms can be revealed by Snoek-Köster (SK) peak observed in deformed iron-based alloys [11][12][13][14][15][16][17][18][19][20]. The interactions between dislocations and shortrange mobile carbon atoms can be assessed by the dislocationenhanced Snoek peak in iron-based alloys [11,16,[19][20][21][22][23][24]. It is important to note that the dislocation-enhanced Snoek peak is observed in ultra-high purity and technical purity Fe-C alloys containing very low concentration of carbon atoms [16,20,21,23].…”

“…Mechanical spectroscopy is considered as a powerful technique to obtain critical information concerning the dislocation-carbon interactions in steel from dislocation-based relaxation phenomena [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. For example, mobile dislocation segments dragging along with them the Cottrell cloud of long-range mobile foreign interstitial atoms can be revealed by Snoek-Köster (SK) peak observed in deformed iron-based alloys [11][12][13][14][15][16][17][18][19][20].…”

“…The Snoek-Köster and dislocation-enhanced Snoek peak are used for evaluating the amount of foreign interstitial atoms and the dislocation density. It is important to emphasize that Snoek-Köster peak (or equivalently, the cold-work peak) [11][12][13][14][15][16] occurs both in deformed ferrite [11][12][13][14][15][16][17][18][19][20] and in martensite [11,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39].…”