Development of Microstructure and Crystallographic Texture during Stationary Shoulder Friction Stir Welding of Ti-6AI-4V

摘要

Electron backscattering diffraction (EBSD) was used to study a stationary shoulder friction stir weld in Ti-6A1-4V. Weld temperatures exceeded the ?-transus, resulting in a supertransus zone (STZ) that encompassed all of the thermomechanically affected zone (TMAZ) and a portion of the heat-affected zone (HAZ). Standard EBSD provided limited information on the material behavior at high temperature in the ? phase field, so in-house software was used to reconstruct the crystallographic orientations of the high-temperature ? phase. The portion of the HAZ that lay within the STZ exhibited the same ? texture at high temperature as the retained ? phase in the unaffected parent material. In the TMAZ, material was deformed in the high-temperature ? phase field and, on cooling, transformed to a_ fully lamellar microstructure.