Stabilization of Lattice Defects in HPT-deformed Palladium Hydride

Recent investigations on palladium hydride (Pd-H) showed, for the first time, evidence of formation of vacancy-hydrogen (Vac-H) clusters during Severe Plastic Deformation (SPD) effected by High Pressure Torsion (HPT). Vacancy concentrations produced in Pd-H by this method are extraordinarily high. DSC-scans show that the thermal stability range of vacancies is extended by about 150K due to trapping of hydrogen leading to the formation of vacancy-hydrogen clusters. Recent experiments give evidence that the mobility of the H atoms and/or the vacancies is conditional for the formation of Vac-H clusters during HPT. Results furthermore indicate defect stabilization by hydrogen trapping not only for vacancy-type defects but also for dislocations and grain boundaries.