Study of order–disorder transitions in Fe–Ge alloys and related anelastic phenomena

Several methods were used to study the phase transitions and related anelastic mechanisms in some alloys of the Fe–Ge system. Obtained results show the appearance of the DTA and dilatometric effects at temperature 200–350 °C due to ordering process corresponding to the peak on internal friction curves (denoted as the P3 peak in this paper). The formation of ordered structure in Fe–Ge system at low Ge concentration is sensitive to the thermal history of the specimen. The formation of the ordered structure (with activation energy of ordering H ≈ 1.14 eV for a concentration of 12 at.% Ge) leads to the increase in the microhardness of studied alloys.

► The Fe–Ge alloys undergo several order-disorder transformations.
► Several thermally activated internal friction peaks are detected.
► The activation energy of the disorder (A2) - order (D03) transition equals to 1.14 eV.