Fig. 1 Schematics of LPBF A and LDED B

Fig. 2 AM produces dislocation cells introduced by thermal cycling [67]. A Schematic diagram of the AM thermal cycle. B The selected area electron diffraction pattern of the dislocation wall. C Morphology of the dislocation wall. D The high-resolution image of C

Fig. 3 Morphologies of A the compressed sample and B compression annealed-773, C, D compression annealed-973, E compression annealed-1173, and F compression annealed-1373 [76]

Fig. 4 As-built sample preparation and phase diagram simulation of AM-fabricated HEA with the second phase [83,84]. A Defect-free HEA as-deposited bulk with a well-dispersed γ" phase distribution. B Phase fraction change in elevated temperature range of HEAs

Fig. 5 Microstructure of AM dual-phase nanolamellar HEA [85]. A The optical micrographs of as-printed AlCoCrFeNi2.1 HEA. B Bright-field TEM image of the bcc and the FCC nanolamellae. C Secondary electron micrograph of the nanolamellar structure. D HAADF-STEM image showing the modulated nanostructures within BCC lamellae. E Tensile stress-strain curves of as-built HEA

Fig. 6 SFs morphology observed in HEA [88,89]. A-C The TEM BF images of Si-HEA show the SF at 0% tensile strain A, 17% tensile strain B and 32% tensile strain C. D The as-built HEA microstructure. E HADDF STEM image showing planar slip trace. F BF image of the dislocation slipping in the cell structure. G Dislocation slip prevented by the cell wall and nanoprecipitate. H The activation of multiple SFs during deformation

Fig. 7 Defects in as-built HEA [16,96]. A Gas porosity defects in the original powder observed by SEM. B Magnification image of A. C, D The cracks and pores in as-built HEA

Fig. 8 SEM image of RHEA with multiple remelting [99]. A RHEA deposition. B Deposited RHEA after the second remelting step resulting in a more homogeneous and smooth fabrication. C As-built RHEA obtained after four depositions and remelting steps. D, E EDX elemental maps corresponding to SEM-images A and B

Fig. 9 Substructures in the as-built RHEA [88,89]. A the effect of grain boundary with different SFE on crack suppression. B long and straight dislocations. C dislocation jogs (the yellow arrows) and dislocation loops (the red arrows)

Fig. 10 As-built biological properties of RHEA [121,125,138,139]. A SEM images of wear scars of the Ti0.5ZrNbTaMo, TiZrNbTaMo, Ti1.5ZrNbTaMo, and Ti2ZrNbTaMo. B Visual evidence of mice thigh before and after implantation (MoTa) 0.2NbTiZr alloy. C Models of TPMS lattice with different porosity based on Schoen's gyroid unit cell and the macroscopic morphologies of the SLM-built samples. D Quantitative analysis of cell density