Effects of He2+ irradiation on W-1Ta-ZrC and W-3Ta-ZrC alloys fabricated via SPS

Bulk W-1wt%Ta-0.5wt%ZrC (W-1Ta-ZrC) and W-3wt%Ta-0.5wt%ZrC (W-3Ta-ZrC) alloys were fabricated and subsequently irradiated with 500 keV He 2+ ions at 400 o C. Microstructural analyses indicated that the defect clusters were predominantly nano-sized dislocation loops and He bubbles. The average size of He bubbles in W-1Ta-ZrC (1.2 ± 0.1 nm) is slightly larger than that in W-3Ta-ZrC (1.1 ± 0.1 nm), along with an approximately 6.9% reduction in number density. Conversely, the number density of dislocation loops in W-1Ta-ZrC was about 9.1% higher than that in W-3Ta-ZrC. Irradiation-induced hardening was evaluated using the nanoindentation test and dispersed barrier hardening (DBH) model. The DBH hardness increments agree well with those obtained from nanoindentation measurements. The results demonstrated a significant increase in the hardening rate of W-1Ta-ZrC, reaching 30.7%, which is nearly 7.7% higher than that of W-3Ta-ZrC. This work systematically investigated the influence of Ta content in the evolution of He-induced defects, irradiation swelling, and hardening in Ta-containing W alloy, providing valuable insights for the development of advanced plasma-facing materials.