Mössbauer kinetics study of the clustering-ordering synergy during the ageing of high carbon Fe−C martensite

Abstract

The kinetics of the isochronal ageing of 1.7–1.9 wt% C iron martensite made from 200 K to 450 K is done by following the Mössbauer spectra run at 10 K intervals for varying ageing times of 1, 10 and 100 hours. A new analysis, similar to that used in constant heating rate measurements of resistivity, calorimetry and dilatometry, is made here and shows that the two steps of clustering and ordering prior the in situ transformation into ε-η carbide have exactly the same activation energy of 75±2.5 and 74±1.5 kJ.mol⁻¹, respectively. The clustering-ordering synergy is discussed.