Irradiation Damage Independent Deuterium Retention in WMoTaNbV

Abstract

High entropy alloys are a promising new class of metal alloys with outstanding radiation resistance and thermal stability. The interaction with hydrogen might, however, have desired (H storage) or undesired effects, such as hydrogen-induced embrittlement or tritium retention in the fusion reactor wall. High entropy alloy WMoTaNbV and bulk W samples were used to study the quantity of irradiation-induced trapping sites and properties of D retention by employing thermal desorption spectrometry, secondary ion mass spectrometry, and elastic recoil detection analysis. The D implantation was not found to create additional hydrogen traps in WMoTaNbV as it does in W, while 90 at% of implanted D is retained in WMoTaNbV, in contrast to 35 at% in W. Implantation created damage predicted by SRIM is 0.24 dpa in WMoTaNbV, calculated with a density of 6.044×1022 atoms/cm3. The depth of the maximum damage was 90 nm. An effective trapping energy for D in WMoTaNbV was found to be about 1.7 eV, and the D emission temperature was close to 700 °C.

Solubility of Hydrogen in a WMoTaNbV High-Entropy Alloy

“…The above mechanisms prevent hydrogen concentrations from reaching the highest possible ratios at room temperature, but also help retain much of the hydrogen once it is absorbed, as found in Ref. [ 18 ]. The limited diffusion due to local strains and chemical diversity may add to the energy barrier created by a primary trap, making its de-trapping energy higher.…”

“…The prospective for industrial applications of high-entropy alloys underline the importance of gaining qualitative knowledge about the processes influencing the absorption of hydrogen. In previous research, a number of V-rich HEAs have been observed to absorb hydrogen, this includes the WMoTaNbV alloy studied in this work [ 17 , 18 ]. The WMoTaNbV efficiently traps hydrogen, with an energy of ∼1.7 eV [ 18 ].…”

“…In previous research, a number of V-rich HEAs have been observed to absorb hydrogen, this includes the WMoTaNbV alloy studied in this work [ 17 , 18 ]. The WMoTaNbV efficiently traps hydrogen, with an energy of ∼1.7 eV [ 18 ]. The exchange between the H and D isotopes, however, occurs at temperatures related to much lower energies, indicating a similarity between the trapping of two isotopes H and D [ 19 ].…”