In Situ High-Energy Synchrotron X-Ray Diffraction Reveals the Role of Texture on the Activation of Slip and Twinning during Deformation of Laser Powder Bed Fusion Ti-6Al-4V

The deformation behavior of Ti-6Al-4V processed by laser powder bed fusion (LPBF) is investigated by in situ high-energy synchrotron X-ray diffraction (HEXRD) during uniaxial compression. The initial microstructure of the alloy consists of a fine lamellar alpha + beta microstructure where alpha lamellae are separated by thin continuous beta layers within prior beta grains. The anisotropy of the alloy is studied in the deformation direction using samples that are built at the angles of 0 degrees, 45 degrees, and 90 degrees with respect to the LPBF base plate. The sample oriented at 0 degrees presents higher strength-ductility trade-off compared with the conditions oriented at 45 degrees and 90 degrees. The in situ HEXRD experiments continuously reveal the microstructure response during deformation and that the textures for each orientation are associated with a different activation sequence of deformation mechanisms.