Effects of welding position, heat treatments, and surface roughness on the fatigue behavior of welded aluminum alloys using friction stir welding

الملخص EN

The present work is aimed to study the fatigue behavior of friction stir welding for the similar and dissimilar joints taking into account the effects of welding position, post welding heat treatments, and surface roughness.

The materials were used AA2024T3 and AA6061T6.

The maximum welding efficiency achieved at friction stir welding process was 62.

8 % of the base metal for the similar 2024-T3 joint, and this value was improved by using post welding heat treatments and reach to 67.

9 %.

Results showed that fatigue strength at 106 cycles depended strongly on welding line position where for welding line at a distance 0.

35L from loading side, the reduction in fatigue limit with respect to 2024T3 base material was 45 % for similar joint and 58 % for dissimilar joints, and for welding line at a distance 0.7 L, the reduction in fatigue strength was 56 % for similar joint and 67 % for dissimilar joints.

While, it was a large reduction in the fatigue strength reaching to 70 % in both similar and dissimilar joint for the welding joint at a distance L (i.

e at the fixing end).

The heat treatments improved the fatigue strength about 31% more than non heat treatments of the similar 2024T3 joint by fsw at 0.7L in high cycle regime.

Finally, the non-finishing samples showed a reduction in fatigue strength reaching to 10 % more than the finishing samples of the similar 2024T3 joint at 0.

7L.