Difference approach to the analysis of resistivity recovery data for irradiated short-range ordered alloys

Abstract

Electrical resistivity recovery (RR) data for irradiated concentrated alloys typically consist of two inseparable parts, one resulting from defect annihilation and the other from short-range order (SRO) effects. These parts exhibit different behaviour and often follow opposite trends. Therefore, in this case, analysis of RR data within the conventional method is too complicated. A new approach to data analysis of such a two-component RR is proposed. The approach involves a new quantity, the difference RR (DRR), which is composed of RR dependences of two similar samples irradiated to different defect concentrations. It is shown that the SRO formation proper and the stages corresponding to the onset of long-range migration of Frenkel pair defects, formed in each part of RR, can be clearly related to certain features of the DRR plots. This interrelationship allows detecting and identifying these stages in each part of RR separately. The validity of the approach is illustrated by analysis of the available pairwise RR data for Fe–16Cr–20Ni and Fe–4Cr alloys. It makes it possible to detect the small contribution from the SRO formation to RR in Fe–4Cr, which we failed to observe previously. It is shown that stage III of Fe–4Cr, which has a negligible contribution to the part of RR induced by defect annihilation, is clearly observed in the part induced by SRO formation.

Keywords:

• short-range order
• metallic alloys
• point defects
• radiation damage
• recovery
• resistivity

Acknowledgements

The work was done within the RAS Program (project 13394). The author is grateful to Dr D.A. Terentyev (SCK-CEN, Belgium) for investigating the numerical solutions of rate equations and to Dr S.L. Dudarev (UKAEA) for editing the text.

Notes

Notes

1. According to the model, fast FP defects recombine with immobile slow FP partners and form immobile clusters, including dimers. The rate equations were derived and numerically solved by Dr D.A. Terentyev using an approach described in J. Nucl. Mater. 352 (2006) p.42 with a set of parameters corresponding to the case of migration of self-interstitial atom defects in α-iron.

2. We did not present the DRR spectrum of Fe–16Cr–20Ni since the raw RR data scanned from Figure 4 in 7 contained sufficiently large uncertainties in the temperature positions of the data points.