Fig. 1 Thermal evolution in the EBM process [7]

Fig. 2 Range of properties available to the engineer through foaming: a density; b thermal conductivity; c Young’s modulus; d compressive strength [55]

Fig. 3 Optical micrographs showing different microstructures for a a bulk material, b a foam [73]

Fig. 4 Charts summarizing the relationship between relative density and relative modulus of elasticity a and relative compressive strength b derived from Ti-6Al-4V cellular structures [79]

Fig. 5 Variation of effective E as a function of porosity [82]

Fig. 6 Mechanical behaviour of the graded lattice structure [69]

Fig. 7 Experimental results for relative Young’s modulus from literature

Fig. 8 Nominal stress-strain curves for configuration 1 with an l/d ratio of 2.5 a and configuration 2 with an l/d ratio of 1.5 b [70]

Fig. 9 Nominal stress-strain curves at different temperatures for configuration 1 a, c, e and configuration 2 b, d, f [70]

Fig. 10 TEM micrographs of the mesh sample with density of 1.68 g/cm3, in which a is bright-field image, and b and c are dark-field images taken from the diffraction spots of the β phase and the α’ martensite noted by arrows in diffraction pattern d [66]

Fig. 11 A strain-cycle diagram showing the trends of strain accumulation for different load conditions [72]

Fig. 12 FESEM surface images of as-fabricated a, surface-etched b and machined c specimens; surface conditions of as-fabricated a’, surface-etched b’ and machined c’ specimens observed under Alicona IFM [89]

Fig. 13 Images showing a global octet-truss unit cell a, a 3D reconstruction of one strut b an isometric view of a 1 mm strut c [90]

Fig. 14 a Comparison between the CAD design (in blue) and the build struts (in green) at different construction angles; b aspect ratio with respect to construction angle [57]

Fig. 15 Relative elastic modulus with respect to relative density for different strut sizes: green curve for DCAD, the red dashed curve for DEQNUM, the orange curve for DEQGEOM. Experimental results are depicted in black [57]

Fig. 16 Computed tomography (CT) images showing porosity in red; a as-built condition, b after HIP conditions [51]

Fig. 17 Optical micrographs of as-built condition a with three different locations of interest b, c, d [48]