Plastically deformed samples of ultra high purity iron (UHP) doped with 150 ppm of niobium were investigated by differential
temperature scanning calorimetry (DTSC) determining the stored energy and the activation enthalpy of recovery and recrystallization.
Any oxidation effects were successfully prevented with a newly constructed device for cleaning the specimens by ion-etching
and enclosing them hermetically in noble metal capsules without any contact to air. Compared with pure iron the stored energy
and the activation enthalpy are increased in the Fe–Nb alloy resulting in a large shift of the recrystallization temperature.