Analysis of Relaxation Processes in HNS Due to Interstitial-Substitutional Pairs

Mechanical Spectroscopy (MS) tests have been performed on a high nitrogen (0.8 wt %) austenitic steel (HNS) with resonance frequencies in the range of kHz. Two sets of samples have been examined: the first set in an as-prepared condition, the second one submitted to a heat treatment of 2 h at 800 °C, which induces a discontinuous precipitation of Cr2N phase. In both sets, the damping spectrum shows a broad peak whose position and shape is changed by the precipitation of Cr2N phase. The results are explained by considering interstitial-substitutional (i-s) interactions.