Microstructural Evolution During Friction Stir Welding of Near-Alpha Titanium

摘要

The microstructural evolution occurring around the tool was investigated in friction stir welds of the near-alpha alloy, Ti-5111. Specifically, the purpose of this investigation was to determine how the material ahead of the tool was influenced by the rotating tool to produce the refined grain structure observed adjacent to the tool and in the tool wake. This involved characterizing the base plate microstructure to show the original beta grain structure and its decomposition to form specific combinations of alpha lath orientations. The microstructure and texture of the final refined grain structure near the tool and in the deposited weld is also discussed.