Microhardness
The Vickers microharness profiles of the friction stir processed FSWed
joints are presented in Figure 4. The microhardness profile of the
AA6082/AA8011 joint showed a decreasing path from the advancing side
across the nugget zone (NZ) towards the reatreating side. The
microhardness profile of AA8011/AA6082 joint showed a gradual increase
from the advancing side towards the retreating side. The maximamum
microhardness value of about 72 HV for AA6082/AA8011 joint was recorded
next to thermos-mechanically affected zone (TMAZ) of AA6082. The maximum
microhardness value of about 56 HV for AA8011/AA6082 joint was also
recorded on the TMAZ region of AA6082. Both microhardness values of the
friction stir processed joints were both lower compared to the base
metals and this behaviour is normally associated with dissimilar
aluminium alloyjoints [33-35].