Tensile and fatigue behavior of SZ, HAZ and BM in friction stir welded joint of rolled 6N01 aluminum alloy plate

• The small bar specimens were extract from SZ, HAZ and BM of the joint.
• Fatigue tests of small bar specimens were done to discuss the local fatigue strength.
• The fatigue strength at SZ exhibited higher fatigue strength than that at BM.
• The higher fatigue strength of SZ was due to fine grains and cyclic hardening.
• Fatigue failure of large plate specimen occurred in HAZ with the lowest hardness.

Tensile and fatigue behavior of a 6N01 aluminum alloy friction stir welded (FSW) joint was studied. The tensile and fatigue tests were carried out for the large plate and small round bar specimens. The small round-bar specimens extracted from base material (BM), heat affected zone (HAZ) and stir zone (SZ). The HAZ exhibited the lowest hardness. The higher tensile and fatigue strengths of SZ were mainly due to fine and homogeneous grains and significant cyclic hardening. Fatigue failure of the large plate specimen including the whole FSW joint part occurred at the lowest hardness location in the HAZ.