Discontinuous precipitation in a high-nitrogen austenitic steel

摘要

The discontinuous precipitation of a high-nitrogen (0.8 wt%) austenitic steel has been investigated after successive steps of heat treatment at two different temperatures (800 and 850°C). After each step of heating the material has been examined by X-ray diffraction (XRD), optical microscopy (OM), transmission electron microscopy (TEM), Auger electron spectroscopy (AES) and microhardness tests. The precipitation of Cr_2N induces the formation of a secondary austenitic phase, leads to the redistribution of N between transformed and untransformed zones and to local variations of mechanical properties.