Blistering and hydrogen retention in poly- and single- crystals of aluminum by a joint experimental-modeling approach

Abstract : Aluminum samples have been exposed to a hydrogen plasma generated by a low-pressure-high-density microwave reactor. Aluminum has been chosen as a surrogate for Beryllium. The fluence was kept below 4 × 10 24 ions/m 2 , in order to study the first steps of nucleation and growth of surface and bulk defects, i.e. blisters and bubbles. Experimental analyzes and macroscopic rate equation (MRE) modeling on poly-and single-crystals were made to investigate the role played by grains boundaries in the hydrogen retention. Temperature programmed desorption (TPD) on Al poly-crystals revealed the production of aluminum hydrides (alanes) as majority species in the desorption flux. Comparison of microscopy observations for three different single-crystal orientations (〈100〉, 〈110〉 and 〈111〉) allowed to determine preferential orientations able to attenuate the formation of blisters.