PSI - Issue 83

Daniele Cortis et al. / Procedia Structural Integrity 83 (2026) 3–13

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Fig. 1. Round cross-section tensile test piece: geometry and dimensions (mm).

Fig. 2. Flat cross-section tensile test piece: geometry and dimensions (mm).

Table 3. Number and geometry of tensile test pieces produced.

Temperature (°C)

N. of round cross-section test pieces (YS, UTS, A)

N. of flat cross-section test pieces (E, ν )

-100

3 3 3 3

1

+22 (room temperature)

+100 +200 Total

1

12

2

After production, tensile test pieces were removed from the building platform using Electrical Discharge Machining (EDM) and they were subjected to 4 hours of aging at 350 °C [Belelli et al. (2022)]. Finally, round cross-section test pieces were subjected to wet tumbling, using a specific machine developed for additive manufacturing application (i.e., Rosler AM Solution - M1) to reduce the surface roughness and to avoid possible fracture sources on the as-built surface. Three different cycles, each of 8 hours, with three different grinding media were used for this purpose: the first and the second with plastic media for the polishing and a third one with ceramics for the finishing. A picture of the rounded cross-section test pieces after the tumbling is shown in Fig. 4 (a). On the other hand, flat cross-section test pieces were left with the as-built condition, Fig. 4 (b). The surface roughness (Sa) of test pieces was measured using an optical microscope (i.e., KEYENCE VHX 7000) with focus variation technology [EN ISO 25178-6 (2010)]. The results show that the Sa decreases to ~1.5 µm compared to the flat cross-section test pieces of ~5.2 µm.