PSI - Issue 83

Ahmad Issmail et al. / Procedia Structural Integrity 83 (2026) 229–238

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The obtained values of the UTS and EaB are in line with those reported by the manufacturer for the same heat treatment (Table 2). For the sake of a quick insight into the annealing and aging heat treatment effects, Table 2 also reports UTS and EaB values of the as-manufactured specimens declared by the manufacturer. Overall, T6 resulted in a decrease in strength and an increase in ductility, which is owed to the diffusion and spheroidization of the Si particles from the interdendritic Si-network, determining a decrease in the strain hardening rate [14, 15, 21].

Fig. 3: (a) Stress-strain curves of the standard specimens at different build orientations; (b) the corresponding values of ultimate tensile strength (UTS); and (c) elongation at break (EaB)

Table 2: Comparison of the tensile properties of PBF–LB AlSi10Mg obtained in the current study and those declared by the manufacturer

Heat Treatment

UTS [MPa]

EaB [%]

Surface Condition

Build Orientation

Study

Geometry

S|V 315 15.9 % S|45° 317 10.3 % S|H 313 9.2 %

Current Study

Flat

as–Built

T6HT

Vertical

310 11 % 320 11 % 460 6.3 % 450 10.2 %

T6 HT

Horizontal

Manufacturer [17]

Round Machined

Vertical

as– Manufactured

Horizontal

3.3. Fatigue Behavior The experimental fatigue results of the different specimen categories, elaborated with both ASTM E739 and the Maximum Likelihood Estimation (MLE) method, are illustrated in Fig. 4. The fatigue limit (considered at 2×10 6 cycles) of the standard specimens calculated with MLE (113.7 MPa) (see Table 3) is comparable (9.8% lower) with the fatigue limit extracted from the study of Aboulkhair et al. [22] (≈126 MPa) conducted at the same stress ratio (R = 0.1) on as-built vertical specimens subjected to a comparable HT. In addition, Razavi et al. [23] report a similar value (110 MPa) for as-built vertical specimens with comparable HT but tested at a stress ratio R = 0. The observation of the fatigue performance of different size categories within the 45° orientation shows an overall similar fatigue performance of m|45° and S|45° for the studied range of data, but with S|45° yielding a failure after nearly 500,000 cycles at around 120 MPa, while m|45° exhibits a runout (Fig. 4(a)). The difference in fatigue performance between miniature and standard specimens is more clearly revealed from the comparison between the fatigue limits reported in Table 3 corresponding to the collective S-N curve of each of the size categories depicted in Fig. 4(b) and Fig. 4(c). In fact, miniature specimens displayed a 9% and 4.8% increase in the ASTM E739 and MLE fatigue limits, respectively, and showed runouts at 17.8% higher loads, while also exhibiting a 6.4% decrease in scatter