Microtextural Characterization of Additively Manufactured SS316L After Hot Isostatic Pressing Heat Treatment

Microtextural characterization using electron backscatter diffraction analysis was performed on laser powder bed fusion manufactured SS316L (SS316L). The crystallographic textures of as-printed (AP) and hot isostatic pressed (HIP) samples have been determined using orientation distribution function maps. The AP sample consists of mostly <110>parallel to BD and <100>parallel to BD fiber textures without any clear presence of twins. Conversely, the HIP sample featured <110>parallel to BD and <111>parallel to BD grains. The formation of <111>parallel to BD texture was due to the deformation associated with the HIP process. Moreover, HIP generated a significant fraction of coincident site lattice Sigma 3 boundaries due to the low stacking fault energy of SS316L. These twin boundaries allow considerable plasticity during subsequent deformation. The spacing of deformation twins is wider (1-5 mu m) compared to the subgrain boundaries (0.2-0.7 mu m). Kernel Average Misorientation maps depict the occurrence of dynamic recrystallization, which is assisted by deformation twinning. The results explain the increased ductility of LPBF-produced, HIP processed SS316L without sacrifice to its tensile strength. [GRAPHICS]