Effects of Kr post-bombardment on carbonitrides produced in a low carbon nitrogen-implanted steel

The effects of Kr post-bombardment on carbonitrides produced by N-implantation in a low carbon steel are studied by means of conversion electron Mössbauer spectroscopy, nuclear reaction analysis and Rutherford backscattering technique. The results show two main features: dissolution and reprecipitation of the produced carbonitrides and modification of the thermal behaviour of the precipitates. Recently we have performed similar experiments bombarding samples of the same steel with He and Ar. Comparison of the experiments shows that irradiation with Ar or Kr ions provides the best retention of carbonitrides at 450° C. On the other hand irradiation with Kr ions to the same dpa level is most effective in producing the dissolution and reprecipitation process.