Issue 68

S. Cecchel et alii, Frattura ed Integrità Strutturale, 68 (2024) 109-126; DOI: 10.3221/IGF-ESIS.68.07

Figure 9: Elemental mapping analysis of LPBF 17-4PH solutioned for flat samples. Yellow arrows indicate the areas with higher Cu concentration.

Figure 10: XRD data from the As-built (AB) and solutioned (S) 17-4 PH samples.

Fig. 10 shows the XRD patterns obtained from the analysis of transversal sections of the various conditions analyzed. The lattice distortion entity in the body-centered tetragonal (BCT) martensite for this alloy is very low, due to the limited C concentration (0.036 wt%). As a consequence, XRD technique cannot discerned between peaks corresponding to body centered cubic (BCC) ferrite and BCT martensite, as also reported by Sun et al. [51] and by Alnajjar et al [52]. Therefore, in line with established practice for 17-4PH, both ferrite and martensite are considered to exhibit the BCC structure [51, 52], a convention adhered to in the current study. XRD phase analysis confirms the predominance of the BCC phase ( α peak) with a minor presence of FCC phase ( ϒ peak), indicating retained austenite. Comparing the same geometry of as-built (AB)

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