Phase transformations in the Fe-N system induced by the concomitant use ofion irradiation and temperature

Ion-beam-assisted phase transformation in the Fe-N system has been studied in Fe samples implanted with N. By bombarding with Ar ions at temperatures in the 140 degrees C less than or equal to T less than or equal to 420 degr ees C range, the epsilon-Fe2N --> epsilon-Fe2+xN + epsilon Fe3.2N and epsil on-Fe3.2N + gamma'-Fe4N phase transformations were induced. The ion-assiste d phase transformations were studied as a function of firstly the temperatu re of the substrate, secondly the initial N concentration and thirdly the i rradiation time. The results of the experiments show that the concomitant u se of ion bombardment and temperature induces a given phase transformation at a temperature that is typically 40-50 degrees C lower than that required for thermal annealing alone.