Residual stresses and high cycle fatigue properties of friction stir welded SiCp/AA2009 composites

• High residual stresses existed in FSW SiCp/AA2009 composite joint.
• The FSW joint had a fatigue limit equivalent to that of the base material.
• Fracture occurred in HAZ at high stress amplitudes but moved to NZ at low ones.

3 mm thick rolled SiCp/AA2009 sheet in T351 condition was subjected to friction stir welding (FSW). FSW generated high residual stresses with the peak value occurring in the weld center. While the FSW joint showed a shorter fatigue life than the base material (BM) at stress amplitudes higher than 150 MPa, it had a fatigue life equivalent to the BM at lower stress amplitudes with a fatigue limit of about 100 MPa. In the BM the fatigue crack initiated at the SiCp agglomeration or inclusions; however, in the joint the initiation zone was mainly characterized by the formation of dimples.