Small-scale characterisation of irradiated nuclear materials: Part I – Microstructure

P.D Edmondson,A London,A Xu,D.E.J Armstrong,S.G Roberts

doi:10.1016/j.jnucmat.2014.11.067

P.D Edmondson, A London + Show 3 more

Open Access

https://doi.org/10.1016/j.jnucmat.2014.11.067

Copy DOI

Journal: Journal of Nuclear Materials	Publication Date: Nov 26, 2014
Citations: 16	License type: cc-by

Affiliation: University of Oxford

Abstract

The behaviour of nanometre-scale precipitates in oxide dispersion strengthened (ODS) ferritic alloys and tungsten–rhenium alloys for nuclear applications has been examined by atom probe tomography (APT). Low Re content tungsten alloys showed no evidence of Re clustering following self-ion irradiation whereas the 25at.% Re resulted in cluster formation. The size and composition of clusters varied depending on the material form during irradiation (pre-sharpened needle or bulk). These results highlight the care that must be taken in interpreting data from ion irradiated pre-sharpened needles due to the presence of free surfaces. Self-ion irradiation of the ODS ferritic alloy resulted in a change in the composition of the clusters, indicating a transition from a near-stoichiometric Y2Ti2O7 composition towards a Ti2YO5.

Highlights

The generation of nuclear reactors – both fission and fusion – will see the materials from which they are constructed being subjected to greater extremes than those currently in service; these extremes primarily being high temperatures and greater damage levels [1,2]
The class of steels known as oxide dispersion strengthened (ODS) ferritic alloys consist of a dispersion of ultra-fine oxide particles throughout the matrix
Following ion irradiation the samples were prepared from the bulk material for atom probe analysis using a focussed ion beam (FIB) technique [26]

Summary

Introduction

The generation of nuclear reactors – both fission and fusion – will see the materials from which they are constructed being subjected to greater extremes than those currently in service; these extremes primarily being high temperatures and greater damage levels [1,2]. Two highly prominent materials for advanced reactor designs are oxide dispersion strengthened ferritic alloys (including the nanostructured ferritic alloy class) and tungsten. Both of these materials can suffer from radiation-induced microstructural changes that are detrimental to the mechanical properties of the alloys

Tungsten

Oxide dispersion strengthened ferritic alloys

Oxide dispersion strengthened steel–14YT