Interaction of hydrogen and helium with nanometric dislocation loops in tungsten assessed by atomistic calculations

The interaction of H and He interstitial atoms with ½〈1 1 1〉 and 〈1 0 0〉 loops in tungsten (W) was studied by means of Molecular Static and Molecular Dynamics simulations. A recently developed interatomic potential was benchmarked using data for dislocation loops obtained earlier with two other W potentials available in literature. Molecular Static calculations demonstrated that ½〈1 1 1〉 loops feature a wide spectrum of the binding energy with a maximum value of 1.1 eV for H and 1.93 eV for He as compared to 0.89 eV and 1.56 eV for a straight ½〈1 1 1〉{1 1 0} edge dislocation. For 〈1 0 0〉 loops, the values of the binding energy were found to be 1.63 eV and 2.87 eV for H and He, respectively. These results help to better understand the role played by dislocation loops in H/He retention in tungsten. Based on the obtained results, a contribution of the considered dislocation loops to the trapping and retention under plasma exposure is discussed.