PSI - Issue 24

Jacopo De Nisi et al. / Procedia Structural Integrity 24 (2019) 541–558 Paolo Folgarait et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Table 5 . x500 (50 micron) metallographic sections (position E), Vilella etched. Apparent precipitation density. Location/Group A1 B1 Q5 (E)

A2

B2

All groups exhibit a fully martensitic microstructure and no presence of δ -ferrite. For groups 0, A1, and B1 (see Table 4 ) the microstructure at x500 shows to be characterized by mixed columnar and equiaxial grains and homogeneously dispersed precipitates (apparent density increasing with ageing and holding time). For the same groups, a higher equiaxial/columnar grains ratio is appreciable in position E with respect any other quadrant (E being the central quadrant in the building platform).