PSI - Issue 82

J. Blankenhagen et al. / Procedia Structural Integrity 82 (2026) 37–43 Blankenhagen et al. / Structural Integrity Procedia 00 (2026) 000–000

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similar fatigue crack growth characteristics within the investigated ∆ K range. While 316L shows a more pronounced orientation e ff ect, Printdur ® HSA demonstrates a more stable and isotropic response. These results suggest that the microstructural refinement and strengthening mechanisms inherent to Printdur ® HSA cane ff ectively mitigate the orientation-dependent weaknesses typically observed in additively manufactured austenitic steels. Consequently, the alloy exhibits promising potential for structural applications that require consistent fatigue performance, regardless of the direction of crack growth.

Printdur® HSA:

10 -2

Specimen

Paris Paris -Exponent m -Coe ffi cient C

PBF-LB/M/PDHSA 1 PBF-LB/M/PDHSA 2 PBF-LB/M/PDHSA 3 PBF-LB/M/PDHSA 4 PBF-LB/M/PDHSA 5 PBF-LB/M/316L 1 PBF-LB/M/316L 2 PBF-LB/M/316L 3 PBF-LB/M/316L 4 PBF-LB/M/316L 5

10 -3

4 . 01 × 10 − 9 3 . 70 × 10 − 9 1 . 58 × 10 − 9 1 . 90 × 10 − 9 7 . 94 × 10 − 9 2 . 29 × 10 − 8 2 . 19 × 10 − 8 3 . 39 × 10 − 8 1 . 57 × 10 − 9 2 . 44 × 10 − 9

PBF-LB / M / PDHSA1 ⊥ PBF-LB / M / PDHSA2 ⊥ PBF-LB / M / PDHSA3 ⊥ PBF-LB / M / PDHSA4 ∥ PBF-LB / M / PDHSA5 ∥ PBF-LB / M / 316L1 ⊥ PBF-LB / M / 316L2 ⊥ PBF-LB / M / 316L3 ⊥ PBF-LB / M / 316L4 ∥ PBF-LB / M / 316L5 ∥

3.11 3.16 3.38 3.26 2.93 2.60 2.60 2.48 3.36 3.27

316L:

10 -4

10 -5

10 -6

10 -7

2

4 6 8

10

20

40 60 80

100

∆ K inMPa √

(a)

(b)

® HSA, (b) Paris law parameters m and C (for

Fig. 3: (a) Results of the crack propagation tests for PBF-LB / M / 316L and for PBF-LB / M / Printdur ∆ K inMPa √ m and da / dNinmm / cycle) for PBF-LB / M / 316L and for PBF-LB / M / Printdur ® HSA

4. Conclusion and outlook

Based on the experimental investigations, the following conclusions can be drawn regarding the crack propagation behavior of PBF-LB / M / 316L and PBF-LB / M / Printdur ® HSA:

• For PBF-LB / M / 316L, literature typically reports crack growth rate curves with identical slopes but varying intercepts. In contrast, the present results indicate that the slope of the PBF-LB / M / 316L Paris law exhibits a dependence on the notch orientation. • PBF-LB / M / 316L specimens with a notch parallel to build direction tend to show a slower crack growth rate, which may be attributed to the microstructural defects induced by the layer-wise manufacturing process. • Conventionally manufactured reference materials showed lower crack propagation rates than additively manu factured specimens tested in this study. • For PBF-LB / M / Printdur ® HSA, only a minor influence of the notch orientation on the crack propagation rate was detected, indicating the possibility for a more isotropic microstructural behavior compared to PBF LB / M / 316L. • Overall, both alloys exhibit a comparable fatigue crack growth behavior within the investigated ∆ K range. • Expanding the dataset by performing additional fatigue crack growth tests on both parallel and perpendicular notched specimens to enhance statistical significance. • Determining fracture toughness parameters ( K IC and J IC ) of the investigated materials. • Evaluating the threshold stress intensity factor range ( ∆ K th ). • Investigating the potential for a unified set of Paris law coe ffi cients applicable to austenitic stainless steels produced via PBF-LB / M, aiming at generalized design correlations for fatigue crack growth prediction. Future work should focus on the following aspects: