Fuller and Mahoneyanalysed the friction stir processing effect on the microstructure and mechanical properties of
5083-H321 aluminium gas metal arc welds, achieving a fatigue
resistance increase of 30% at 107
cycles under four-point bending
fatigue tests. The increase of the fatigue strength was due to
grain-size grain refinement, precipitate strengthening, which was
induced by breakup and formation of a higher volume fraction of
precipitates, and near surface defects removal