Synergistic effects of He, Fe, and deuterium ions on tungsten

Abstract

Plasma-facing materials (PFMs) in fusion reactors are subjected to irradiation by high-energy neutrons and high flux plasmas during operation. Especially, in the presence of helium (He), irradiation can significantly exacerbate the degradation of material properties. Hence, experimentally investigating the irradiation tolerance of PFMs under the combined effects of He, neutron, and plasma irradiation is essential for ensuring the safe operation of fusion devices. Here, heavy-ion simulations of neutrons were utilized to investigate the synergistic effects of He/Fe/D ions on the microstructural and micromechanical properties of tungsten PFMs. The results show that He + Fe dual-ion irradiation leads to significant irradiation hardening, which is attributed to the increase of both the density and size of dislocation loops. The annealing effect of pre-damaged W under D plasma exposure is considered to be the primary factor driving the evolution of dislocation loops. The significant reduction in the number density of dislocation loops is considered to be the main factor contributing to the reduction in hardening increment after d-ion implantation. To our knowledge, this is among the first studies to simulate the evolution of defects and nanohardness in W PFMs in fusion reactors under the combined influence of He, displacement damage and plasma. This research offers insights into the irradiation damage effects of PFMs in fusion reactors and serves as a reference for the development of new W-based alloy materials.