▎ 摘　　要

The influence of graphene oxide (GO) on selective laser melting (SLM) of Ti-48Al-2Cr-2Nb (at.%, Ti-4822) has been investigated using three-dimensional (3D) focused ion beam-scanning electron microscopy (FIB-SEM) tomography. The reconstructed 3D images from FIB-SEM tomography reveal the micro-/nano-features in the SLMed Ti-4822, including the dual-phase (alpha(2) + gamma) cellular structure and various types of defects. With the addition of 0.3 wt.% GO, the formed alpha(2) cells are significantly refined, the gamma phase network becomes thinner and more tightly packed, and the volume fraction of gamma phase increases while that of alpha(2) decreases. In addition, micro-cracks and nano-pores are observed in the SLMed Ti-4822, while only nano-pores with dramatically reduced size and number density are characterized in the SLMed Ti-4822 with GO. Our 3D characterization results have provided experimental evidence indicating that the addition of GO can improve the manufacturability of SLM of Ti-4822.