Micro-mechanical investigations of irradiation tolerance in nanostructured ferritic alloys processed into thin-walled tubing
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Authors
Harvey, Cayla
Issue Date
2022
Type
Dissertation
Language
Keywords
Alternative Title
Abstract
The contribution of this thesis to science is studying a newer class of oxide dispersion strengthened steel shaped into thin walled tubing by comparing different thermos-mechanical processing paths. Additionally, this work investigates the properties and microstructure of those materials using high-throughput micro-mechanical techniques before and after ion irradiation. Specifically, this work shows the use of sharp indentation, spherical nanoindentation, micro-pillar compression, and micro-tensile testing techniques. The first part of the dissertation explores the different techniques on varied material systems. The second part applies these characterization methods to one specific steel in order to evaluate the effect of the processing method on the properties. Testing at a nanometer scale to tens of micrometers length scale was critical for the study after proton irradiation, which occurs on a similar length scale into the surface of the material. This enables testing on a shorter time frame than waiting for large pieces of materials after neutron irradiation. The findings show irradiation of a particular ion specie combined with a micro-mechanical technique applied at same length scale can provide useful information to evaluate candidate materials for nuclear applications. It was found that the two processing pathways at lower temperatures resulted in smaller grain sizes and therefore, higher strengths and less of a change in strength after proton irradiation.