Kinetics of Hydrogen Desorption from Rapidly Solidified Al-Cr Alloys

The thermal desorption spectroscopy has been applied to analyse hydrogen desorption from foils of Al-Cr alloys containing up to 3.0 mol% Cr produced by centrifugal melt quenching. Surface morphology of the alloys was monitored using atomic force microscopy and scanning electron microscopy. It was revealed that hydrogen behaviour is strongly affected by microstructural features available due to rapid solidification and represents at least four hydrogen trap sites in Al-Cr alloys. The Cr atoms in lattice sites are identified as predominant trap site. The occupancy of dislocations was estimated to be rather high in contrast to vacancies and pores in alloys. The amount of hydrogen trapped by vacancies is drastically decreased with increase in Cr concentration. These hydrogen/microstructure interactions were discussed regarding rapidly solidified pure aluminum as well as traditionally processed aluminum samples.