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

Abstract

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°C ≤ T ≤ 420°C range, the ε-Fe₂N → ε-Fe_2+x N + ε-Fe_3.2N and ε-Fe_3.2N + γ′-Fe₄N phase transformations were induced. The ion-assisted phase transformations were studied as a function of firstly the temperature of the substrate, secondly the initial N concentration and thirdly the irradiation time. The results of the experiments show that the concomitant use of ion bombardment and temperature induces a given phase transformation at a temperature that is typically 40–50°C lower than that required for thermal annealing alone.