Investigation of Fine Atomic Structure of Low-Activation Chromium Steel Using Mossbauer Spectroscopy and Calorimetry within the Temperature Range of Ductile-to-Brittle Transition

摘要

Using Mossbauer spectroscopy on ~(57)Fe nuclei within the range of ductile-to-brittle transition temperatures, a change in the force constants is revealed mainly in the iron environment with a single atom of chromium in the ferritic-martensitic 12% chromium steel EK 181, and anomalies are also detected in behavior of the effective magnetic fields and the 3d-electron density on the iron nuclei. It is shown that the partial Debye temperature for an iron environment with a single atom of chromium lies within the ductile-to-brittle transition temperature range. From calorimetric measurements of the internal energy of steel, an anomaly in the behavior of the heat capacity is found, which disappears after thermocycling (from -140 to 40℃) and reappears after annealing at 550℃.