Shoulder contact and gas shielding in titanium friction stir welds

Abstract

The effects of inadequate shoulder contact and poor gas shielding were examined in friction stir welds of ATI 425 titanium. Welds with varying oxidation induced surface discolorations due to poor gas shielding and varying amounts of shoulder contact were studied to determine the effects of these parameters on the microstructure, microhardness, and three-point bend test properties of the welds. The effects of these parameters and their effects on the mechanical properties of the resultant weld are discussed.

Keywords:

• Friction stir welding
• Ti 425
• Oxidation
• Microstructure
• Properties

The authors would like to thank Keystone Synergistic Enterprises for providing the welds and for helpful discussions. We would also like to acknowledge the Structural Metallics office of the Office of Naval Research for financial support.