Effects of the grain boundary segregants P, S, C and N on the grain boundary self-diffusivity in α-iron

Morphology and kinetics of discontinuous precipitation and dissolution in an Fe-8.5Al-27Mn-1.0Si-0.92C alloy

“…[2]] and the influence of volume diffusion on the reactions as [27] is used here. Grain-boundary diffusion data for Mn in Fe [29] and Fe in Fe, [32,33] as reported should be held responsible for the discrepancy. In the work in the literature are shown here for comparison.…”

“…According to the theory in Fe. [32] The relatively high activation energies for grainof Aaronson and Liu, the boundary diffusivity was directly boundary diffusion during the DP and DD reactions, in the related to the reaction-front velocity and the lamellar spaccase of the alloy under study, might be attributed to the ing, shown as follows:…”

“…providing good markings for the exact measurement of the In order to evaluate the influence of volume diffusion on the velocities of DP, DD 1 , and DD 2 reactions in this study, the effective diffusion times, t eff , as required to deplete the lamellar DP of excess magnese atoms through volume diffusion to the lamellae, were calculated by applying the around 3.27 ϫ 10 3 s (0.9 hours), thus implying that the volume diffusion had an effect on the velocity of DP. After further employment of the volume diffusivities of 59 Fe in Fe as reported by Hänsel et al, [32] the effective diffusion times for the corresponding reactions were calculated and listed in Table I, as an approximate evaluation of the volumediffusion effect on the kinetics of DP, DD 1 , and DD 2 reactions. It could be seen that the volume diffusion did indeed only two values of D v could be found, given by Lübbehus-sen [29] and Geise and Herzig [30] for the radiotracer measurehave an influence on the way the DP, DD 1 , and DD 2 reactions would proceed from the early stages on.…”

“…These data were also given in Figure 10 for comparison, which indicated that the grain-boundary diffusivities estimated from the kinetics analysis of DP, DD 1 , and DD 2 reactions in the present Fe-8.5Al-27Mn-1.0Si-0.92C alloy were slightly lower than the measured grain-boundary diffusivities of Mn in Fe [29,30,33] and Fe in Fe. [32,33] This discrepancy might be traced to the omission of composition terms in the simplified theory of Aaronson and Liu [q.v., Eq. [2]] and the influence of volume diffusion on the reactions as [27] is used here.…”

“…In most cases, A is a function of the compositions energy for the grain-boundary diffusion of Fe in Fe, as of phases related to the reaction. Because the alloy in the reported by Hänsel et al, [32] were also listed in the table. It current study contained multielements, most kinetics modwas evident that the activation energies for DP, DD 1 , and els [20][21][22][23][24][25][26] were inapplicable because of the difficulty in DD 2 were quite similar, which implied that the atom diffudetermining the A value.…”