Fig. 1: Evidence of high-density Ni-rich LCI entities in as-aged L-PBF NiTi.
a Synchrotron X-ray diffraction profile. b Radial distribution function (RDF) calculated from atom probe tomography (APT) results showing the relationship between bulk normalized concentration (Bulk norm. conc.) and the distance of Ni-Ni pairs. Inset is a 3D reconstruction map of Ni atoms from APT measurement. c HAADF-STEM image and the atomic concentration ratio between Ni and Ti along the red arrow. d Selected-area electron diffraction (SAED) pattern under the [113]B2 zone axis. e Dark-field transmission electron microscopy (TEM) image taken by the aperture positioned in the center of the streaked region in (d) (yellow circle). f HAADF-STEM lattice image. g FFT pattern of (f). h Inverse FFT image taken by the diffuse scatterings of (g) (yellow circles). i, j Simulated Ni concentration maps before and after 108 Monte Carlo/Molecular Dynamics (MC/MD) iterations at 523 K, respectively. k Average diameter (d, red line) and number density (ρ, blue line) of Ni-rich LCI entities as well as potential energy per atom (PE, black line) with respect to MC/MD iteration number.
