Interactions between solute atoms in Fe–Si–Al–C alloys as studied by mechanical spectroscopy

The role of silicon, vacancies, and strain in carbon distribution in low temperature bainite

“…In both ferrite and austenite, the minimum energy of formation, which could be found in the calculations by moving C away from Si, was comparable to the one in pure Fe (+0.7 eV in ferrite and slightly negative in austenite, in agreement with literature results [12,[24][25][26][27]). Thus, the presence of Si does not seem to increase the solubility of C but rather decreases it.…”

“…In general, ab initio results indicate a repulsive interaction of C with substitutional Si in ferrite [24,25] , but the excess solution enthalpy for Fe-C and Fe-Si-strongly depends on the interatomic distance. From the binding energies calculated for the octahedral and tetrahedral positions for C, the activation energy or energy barrier to diffuse the C atom from one octahedral to another octahedral position through the tetrahedral interstitial in a pure Fe system, was determined to be ∆E =0.87 eV [12,24], which agrees well with experimental results [26,27]. The changes of these energy barriers in the presence of Si lead to the effect that at lower C concentrations, Si diminishes the C diffusivity [25].…”

Mechanisms of anelasticity in Fe–13Ga alloy

“…The slight broadening of the peak from the hightemperature side suggests the appearance of a second Snoek-type peak (P2) at higher temperature due to interstitial (C)esubstitutional (Ga) atoms interaction. The broadening of the Snoek-type peak due to appearance of the second ies peak is typical for several FeeCeMe (where Me is a metal with a weak tendency to form carbide) [6], and has been reported for the FeeAl, FeeGe and FeeSi systems earlier in papers [7,13]. It has been shown that the two Snoek-type peaks result from carbon jumps within the FeeCeFe and FeeCeMe (Me ¼ Al, Ge, Si) surroundings, respectively, indicating a long-range elastic interaction between the interstitial C and substitutional solutes in iron.…”

Structure and anelasticity of ordered and disordered Fe–Ge alloys

“…Thus the Zener peak in disordered Fe-Al alloys (w800 K for 1 Hz) can be observed up to 22at%Al and only 11at%Si. It is largely suppressed in ternary Fe-Al-Si alloys due to a mutual compensation of the distortions produced by the big Al and small Si atoms, respectively [43]. P LT The two ''low-temperature'' (P LT1 þ P LT2 ) peaks, measured in both bcc-type and hexagonal Fe-Ge alloys and not explained in detail, are most probably linked with dislocations.…”