Effect of tool shoulder features on defects and tensile properties of friction stir welded aluminum 6061-T6

Six unique tool shoulder designs were produced with the objective of improved metal constraint and flow to the pin. The six tools were made of Ti-6Al-4V by metallic additive manufacturing. Each tool was used to produce butt welds using aluminum 6061-T6 plates. The welds were subjected to nondestructive evaluation and tensile testing to determine weld soundness and strength. A FSW tool shoulder having a raised spiral design produced the weld with the best combination of surface quality and mechanical properties. The additive-manufactured Ti-6Al-4V tooling had good wear characteristics and appears to be a suitable route to rapidly produce unique FSW tool designs.