PSI - Issue 83

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

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Build direction

Fig. 3. Tensile test pieces placement on the building platform: y-axis is the gas flow direction and x-axis the powder spread direction.

(a)

(b)

Fig. 4. Tensile test pieces: (a) round cross-section after wet tumbling; (b) flat cross-section in the as-built surface condition.

2.2. Tensile test setup During tensile tests, round cross-section test pieces were employed with a standard axial clip-on extensometer (i.e., INSTRON 2630-105) to simplify the mounting and unmounting procedure at different temperature; while flat cross section test pieces were employed with a biaxial clip-on extensometer (i.e., INSTRON 2650-561), provided of three independent acquisition channels, two for the axial ( ε a , ε b ) and one for the transversal strains ( ε t ), to evaluate E and ν (equation 2) at the same, time increasing the overall accuracy. Both extensometers have a gauge length of 25 mm. Tensile tests were done by means of a universal testing machine (i.e., INSTRON 68FM100) equipped with a load cell of 100 kN and an environmental chamber (i.e., INSTRON 3119-610) able to reach -150 °C using liquid Nitrogen (LN 2 ), and +350 °C with high-power resistors. Data were acquired according to EN ISO 6892-1 (2020), EN ISO 6892 2 (2018) and EN ISO 6892-2 (2015) standards using a constant strain rate ( ε ’) of 0.00025 ± 20% s -1 (i.e., Method A222) for the determination of YS, UTS, A, and 0.00007 ± 20% s -1 (i.e., Method A1) for the evaluation of E and ν .