Subsurface zone in aluminium studied by positron lifetime spectroscopy

The subsurface zone in the well- annealed pure 99.999% aluminium exposed to the sliding of a graphite pin was studied using positron lifetime spectroscopy. This experimental method allowed to detect the dislocation lines, dislocation lines with opposite jogs and single vacancies that occur during sliding. The type of defect changes upon increase of the sliding time and depends on the distance from the damaged surface. It was established that the total depth of defect distribution depends on the applied load and extends from 150 to 450 mum.