Effect of D on the microstructure evolution and hardness of W-Re films deposited by magnetron sputtering

One of the challenges in fusion reactor research is the development of plasma-facing materials that can endure extreme environments. Although tungsten (W) is regarded as the most promising plasma-facing material, its performance inevitably degrades under fusion reactor conditions. When exposed to low-energy, high-flux hydrogen isotope plasma, W will experience a risk of structural damage. Meanwhile, neutron irradiation will generate transmutation products of W, which can alter the mechanical performance of W alloys. In this work, W-rhenium ( Re ) films with homogeneous deuterium (D) distribution are manufactured by magnetron sputtering to investigate the effects of Re and D on the mechanical performance of W. The damage gradient effect of the prepared samples is effectively mitigated, which has significant advantages compared to samples prepared by ion implantation or plasma exposure. The results indicate that sample hardness would increase with the higher D content, and the hardness-depth relationship follows the Nix-Gao model. At the same D concentration, increasing Re content leads to a reduction in hardness, which can be attributed to enhanced dislocation mobility. Meanwhile, the dislocation density in the sample has a positive relation with D content, which is consistent with the calculation results based on dispersed barrier-hardening model. The increased Re content further reduces D retention in W- Re films by decreasing the concentration of vacancy defects. This study elucidates the effects of Re and D on the mechanical properties of W under fusion reactor conditions.