NSUF 20-4138: In-situ nano-tensile testing of neutron-irradiated HT-9 steel

Structural materials for the Generation IV (Gen IV) reactors will be exposed to temperatures and neutron doses higher than those observed in Light Water Reactors (LWRs). One of the prime candidates for Gen IV structural material is HT-9 steel, which has been demonstrated to have a lower swelling rate after irradiation. However, neutron radiation performance of these steels has to be thoroughly investigated before they can be implemented. It is known that irradiation will produce defects in the microstructure, which over time can cluster and degrade mechanical properties. It is thus imperative to establish microstructure-property relationships for these alloys. Previous work concentrated on mechanical testing of small ion irradiated specimens in transmission electron microscopes (TEM) and large neutron-irradiated specimens in hot cells. In this work, we propose to develop a correlation between microstructure and mechanical properties of neutron-irradiated HT-9 steels at a small scale. The proposed work involves a combined analysis of defect microstructure and mechanical properties using in situ nano-tensile testing inside the Transmission Electron Microscope (TEM). In situ nanomechanical characterization will assist in real-time visualization of the movement of defects under uniaxial tensile load. The results obtained in the form of stress vs. strain curves will be used to calculate material properties such as yield stress and elastic modulus.

Additional Info

Field	Value
Abstract	Structural materials for the Generation IV (Gen IV) reactors will be exposed to temperatures and neutron doses higher than those observed in Light Water Reactors (LWRs). One of the prime candidates for Gen IV structural material is HT-9 steel, which has been demonstrated to have a lower swelling rate after irradiation. However, neutron radiation performance of these steels has to be thoroughly investigated before they can be implemented. It is known that irradiation will produce defects in the microstructure, which over time can cluster and degrade mechanical properties. It is thus imperative to establish microstructure-property relationships for these alloys. Previous work concentrated on mechanical testing of small ion irradiated specimens in transmission electron microscopes (TEM) and large neutron-irradiated specimens in hot cells. In this work, we propose to develop a correlation between microstructure and mechanical properties of neutron-irradiated HT-9 steels at a small scale. The proposed work involves a combined analysis of defect microstructure and mechanical properties using in situ nano-tensile testing inside the Transmission Electron Microscope (TEM). In situ nanomechanical characterization will assist in real-time visualization of the movement of defects under uniaxial tensile load. The results obtained in the form of stress vs. strain curves will be used to calculate material properties such as yield stress and elastic modulus.
Award Announced Date	2020-07-14T14:09:35.383
Awarded Institution	Idaho National Laboratory
Facility	Advanced Test Reactor
Facility Tech Lead	Alina Zackrone, Yaqiao Wu
Irradiation Facility	None
PI	Tanvi Ajantiwalay
PI Email	[email protected]
Project Type	RTE
RTE Number	4138