Analytical characterisation of oxide dispersion strengthened steels for fusion reactors

Abstract

Reduced activation ferritic/martensitic and ferritic steels strengthened by a dispersion of oxide nanoparticles have been considered viable structural materials for fusion applications above 550uC. However, the microstructural stability and mechanical behaviour of these steels subjected to the aggressive operating conditions of these reactors are not well known. An accelerated development of these materials is crucial if they are going to be used in future power reactors. Then, it is indispensable to understand their atomic scale evolution under high temperature and irradiation conditions. The present paper reviews how the combination of transmission electron microscopy and atom probe tomography has been successfully applied for the characterisation of these steels at the near atomic scale, to reveal the nanoparticle structure, grain boundary chemistry and void distribution.

A review of advantages of high-efficiency X-ray spectrum imaging for analysis of nanostructured ferritic alloys

“…For instance, a slight Cr-rich ring surrounds one of the Ti-Y rich particles (designated by arrow in Fig. 2b), confirming an EFTEM result noted by de Castro et al [41] and EDS results noted by Certain et al [42]. Nitrogen is difficult to detect by EDS, particularly in the presence of Ti due to the near-overlap of the N-K and Ti-L X-ray lines, but the EELS data differentiates them clearly, as seen in Fig.…”

Microstructure of HIPed and SPSed 9Cr-ODS steel and its effect on helium bubble formation

“…Interestingly, a coreeshell structure companied with clear lattice mismatch was found at the surface of Y 2 Ti 2 O 7 . It is hypothesized that the Crenriched layer locates at the external of Y 2 Ti 2 O 7 , which has been reported many times by previous studies [28e30, 33,34].…”

Tensile and fracture characteristics of oxide dispersion strengthened Fe–12Cr produced by hot isostatic pressing

“…Forging before the heat treat-ment does not significantly change the microhardness, at least for the heat treated non-ODS Fe12Cr alloy, as the microhardness value is similar to the one found in a non-ODS Fe14Cr alloy forged at 1323 K and subsequently heat treated at 1123 K. When comparing the ODS counterparts, the microhardness value is $ 8% lower in the ODS Fe12Cr than in the forged -heat treated ODS Fe14Cr alloy containing 0.3 wt%Y 2 O 3 particles [12]. The higher homogeneity of the nanoparticle dispersion found in this ODS Fe14Cr alloy would account for the difference in hardness [10,13]. Fig.…”

“…[8][9][10]. The more relevant characteristics of the alloys can be summarized as follows: both ODS and non-ODS alloys present a similar microstructure, composed of martensite laths and a high density of dislocations in the as-HIPed state.…”