INVESTIGATION OF THE EFFECT OF TEMPER CONDITION ON THE FRICTION-STIR WELDABILITY OF AA7075 Al-ALLOY PLATES

摘要

Al-alloys are widely used in the transportation industries due to their low density and excellent formability properties. These alloys, which are problematic in fusion-welding processes, can be successfully joined by friction-stir welding. Particularly high-strength AA7075 alloy is considered to be non-weldable by fusion welding. Friction-stir welding, being a solid-state joining technique, can also be successfully used in joining other difficult-to-weld alloys. In this study, 3.17-mm-thick, AA7075 Al-alloy plates both in the O- and T6-temper conditions were joined by friction-stir welding using four different weld parameters. Microstructural and mechanical characterizations of the joints produced were obtained with detailed optical microscopy investigations, extensive hardness measurements and tensile tests. The effect of temper condition on the joint performance was determined in addition to the effect of the weld parameters on the joint quality.