Issue 53

P. Ferro et alii, Frattura ed Integrità Strutturale, 53 (2020) 252-284; DOI: 10.3221/IGF-ESIS.53.21 261 more irregular. At 1800 mm/s a sudden reduction of the fusion zone dimension was observed, and the melt track became discontinuous. Such discontinuities will result in lack of fusion defects because of the local increase of the layer thickness (as schematized in Fig. 5b). Further increase of laser speed promoted the balling defects formation (Fig. 14) Figure 9: Melt pool depth with scan speed of 0.12, 0.20, 0.28 m/s and comparison with the experiment (laser power = 45 W, material = 316L stainless steel) [34] Figure 10: Molten pool morphology under the influence of gravity (a) and surface tension (b) (from [41]) Figure 11: Melt pool characteristics under different physical effects: (a)–(c) are sliced at the same time under the same process parameters. The red contour corresponds to the liquid fraction of 0.1. (From. [41])