PSI - Issue 82

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

40

4

2.2. Manufacturing parameters

The laser parameter sets employed for specimen fabrication are summarized in Table 2. All samples were produced using an EOS M280 system equipped with a 400 W continuous-wave fiber laser. Nitrogen was used as the shielding gas during the manufacturing of Printdur ® HSA specimens, whereas argon was applied for the 316L specimens to ensure optimal process stability and surface quality. Twodi ff erent notch orientations were investigated. Figure 1 (c) illustrates the specimen geometry and correspond ing notch orientation relative to the build direction are given in Fig. 1 (a) and (b). Initially, rectangular blanks were additively manufactured from both materials. Subsequently, the final compact-tension (CT) specimen geometry was machined from these blanks to achieve the required dimensional accuracy and surface finish for mechanical testing.

® HSA and PBF-LB

Table 2: Used laser parameters for the manufacturing of the PBF-LB / M / Printdur

/ M / 316L specimens

Material

Energy density

Scanning velocity

Laser power

Layer thickness

Hatch distance in µ m

in J / mm²

inmm / s

inW

in µ m

in µ m

® HSA

PBF-LB / M / Printdur PBF-LB / M / 316L

65.97 66.67

600 750

190 200

40 40

120 100

2.3. Test procedure

Fatigue crack growth tests were performed in accordance with ASTM E647 (ASTM International (2023)). All experiments were conducted on an Instron 8032 servo-hydraulic testing machine, equipped with an Instron 8800 digital controller and a ± 100 kN load cell of an accuracy class 0.5. The tests were conducted under load control at a frequency of 18 Hz and a stress ratio of R = 0.1. Crack Opening Displacement (COD) was monitored using an Epsilon COD extensometer (Model 3541-010M-100M-LT). After pre-cracking the specimens to a nominal crack length of 1.65 mm, testing was conducted first with a decreas ing ∆ K range. After that, the tests continued at constant load amplitude to characterize the stable crack growth regime. Crack growth rates (da / dN) were evaluated as a function of ∆ K , and the Paris law parameters m and C were derived to describe the material-specific fatigue crack propagation behavior.

10.0

22.5

12.5

16.25 13.75

M3x1.5

30.0

1.6

12.5

60.0

build direction

10.0

50.0

build direction

(b)

(c)

(a)

Fig. 1: (a) Vertically notched specimen ⊥ with notch parallel to build direction (Figure adapted from Reschetnik et al. (2019)), (b) Horizontally notched specimen ∥ with notch perpendicular to build direction (Figure adapted from Reschetnik et al. (2019)), (c) Used CT-specimen geometry according to ASTM E647 (ASTM International (2023))