Mechanical properties of several perspective nuclear materials studied by tensile and small punch tests: INNUMAT project

The development of fusion and generation IV fission reactors poses huge challenges on the development of structural materials capable to withstand high operating temperatures and severe neutron irradiation. A recently launched European project INNUMAT advances the development of new alloys by assessing ageing and damage in fission/fusion operational conditions e.g. including neutron irradiation, liquid metal corrosion tests and long-term annealing. A systematic comparison has been conducted on seven candidate metallic alloys, including well-characterized alloys such as Eurofer97 and 15-15Ti as well as advanced materials such as high entropy alloys (HEA), oxide dispersion strengthened (ODS) steel and alumina forming austenitic (AFA) steel. The goal is to investigate the microstructure and mechanical properties via hardness, tensile tests, Small Punch Tests (SPTs) and then address the microstructure-property relationships. The ODS steels demonstrate enhanced strength and ductility as compared to Eurofer97, and HEA and AFA steel exhibit a significant improvement of ductility when compared with 15-15Ti. In addition, a good correlation between SPT and tensile results confirms the reliability of SPT techniques which is essential for the application of SPT for future post-irradiation analysis. These results form a solid baseline for the next step of determining the effect of neutron irradiation for these metals.