PSI - Issue 83

Sze Pei Tan et al. / Procedia Structural Integrity 83 (2026) 28–40

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stress amplitudes above 200 MPa, the fatigue life of fabricated specimens is limited, with failure occurring in the low cycle region up to 10 5 . In contrast, T6-treated specimens demonstrate increased fatigue life under comparable stress levels, which indicates the improved resistance to fatigue crack propagation. The present study trend is consistent with literature results, where T6 treatment increases fatigue performance due to improved mechanical stability. Compared with Aboulkhair et al. [29] the overall slope and fatigue trend are similar, confirming the reproducibility of fatigue behavior in DMLS AlSi10Mg. Additionally, The reduced scatter is observed in the samples with T6-heat treated specifies that the heat treatment reduces residual stresses and improves structural homogeneity, contributing to more stable fatigue performance. Overall, the S–N comparison confirms that T6 heat treatment significantly increases fatigue resistance and reduces variability, although AM-induced defects remain an important factor controlling fatigue life.

Table 4. As-built specimens overall fatigue test results. Specimens (UTS) Cycles to Failure

 min (MPa)

 mean (MPa)

 max (MPa)

90 % 80 % 70 % 60 % 50 %

1.08 x 10 3 2.44 x 10 3 5.99 x 10 3 1.03 x 10 4 3.51 x 10 4

280.40 252.36 224.32 196.28 168.24

28.04 25.24 22.43 19.63 16.82

154.22 138.80 123.38 107.95

92.53

Table 5. Heat-treated specimens overall fatigue test results. Specimens (UTS) Cycles to Failure

 max (MPa)

 min (MPa)

 mean (MPa)

90 % 80 % 70 % 60 % 50 %

3.77 x 10 4 6.05 x 10 4 1.99 x 10 5 5.08 x 10 5 2.13 x 10 6

310.20 279.18 248.16 217.14 186.12

31.02 27.92 24.82 21.71 18.61

170.61 153.55 136.49 119.43 102.37

300

Experiment - As-Built Aboulkhair - As-Built Experiment - T6 Aboulkhair - T6

200

100

Maximum Stress, (MPa)

10 3

10 4

10 5

10 6

10 7

10 8

Cycles to Failure, (N)

Fig. 7. Comparison of fatigue behaviour between experimental and previous study [29] for as-built and heat-treated specimens