Magnetic after-effects in α-Fe–Al–C alloys with small Al content

Abstract

Magnetic after‐effects have been investigated in α‐Fe–Al–C samples containing from 0.1% to 1.5% aluminium. Isothermal disaccommodation curves, determined in the case of 0.1% and 0.9% Al in the temperature range between −43 and +24°C, could be decomposed into six relaxation processes (I to VI), described by a discrete spectrum of time constants. Arrhenius law parameters of the relaxation have been calculated. Relaxation II has been proved to be the carbon Snoek relaxation. Relaxations III and I are originated from directional ordering of C‐C and C‐Al pairs, respectively.

Magnetic Susceptibility Disaccommodation and Mössbauer Effect in Microcrystalline Fe-Si Ribbons

“…θ0i was imposed to be 3.2 x 10 -15 s, according to [2,3]. The process with the activation energy equal to 0.84 eV corresponds to the carbon Snoek relaxation in Fe [2,3].…”

“…The Δ(1/χ) = f (T) curves were decomposed into elementary processes, each of them being described by a single time constant. The theoretical curves were calculated using the formula [191: where Qi is the activation energy, θ0i -pre-exponential factor and Ai -relaxation intensity of the i-th process [2,3,19].…”

“…The relaxation spectrum observed in α-Fe containing C or N (e.g. [1][2][3]) appears in the temperature range 245-259 K due to the jumps of interstitials in the vicinity of Fe atoms (the Snoek relaxation). From investigations carried out for α-Fe-3wt%Si alloys in the form of sheets and monocrystals it was found [4][5][6][7][8][9] that the magnetic susceptibility disaccommodation band is considerably broader than in Fe-C(Ν) and consists of two parts:…”