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 × 1024 ions/m2, 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. Keywords: Blistering, Aluminum, Hydrogen inventory