Evaluation of irradiation hardening in ODS-Cu and non ODS-Cu by nanoindentation hardness test and micro-pillar compression test after self-ion irradiation

Abstract

Oxide dispersion strengthened (ODS) Cu alloys are expected to have high strength and superior irradiation resistance that are necessary characteristics for the divertor components of fusion reactors. The present study investigated the irradiation hardening after a self-ion irradiation experiment that was carried out at 100 °C with 5.1 MeV Cu2+ ions up to three displacements per atom in ODS-Cu and compared it to that of non-ODS Cu materials such as mechanically alloyed (MAed) Cu and single crystal (SC) Cu. Nanoindentation hardness tests and micro-pillar compression tests on 1 μm cubic pillars were carried out to evaluate the mechanical strength before and after the ion-irradiation. Both MAed-Cu and ODS-Cu showed good resistance against irradiation hardening, while SC-Cu showed a larger increase in the nanoindentation hardness and in the micro-pillar compression yield stress. Relationships between the nanoindentation hardness, Vickers hardness and micro-pillar yield stress were discussed considering the effects of both specimen/indentation size and irradiation hardening.

Keywords

• Oxide dispersion strengthened Cu
• Self-ion irradiation
• Micro-pillar compression
• Nanoindentation
• Irradiation hardening