PSI - Issue 53

R.F. Fernandes et al. / Procedia Structural Integrity 53 (2024) 144–150 Author name / Structural Integrity Procedia 00 (2019) 000–000

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2022; Maleki, 2022; Nicoletto, 2020). However, it is important to highlight that there is no literature available regarding the investigation of this specific alloy under variable amplitude loading. Thus, an optimized heat treatment with temperatures below the threshold of Si precipitation was developed in order to improve the fatigue strength of the material. The main objective of this work was to investigation the effect of this heat treatment on the fatigue behavior of both notched and unnotched components under variable amplitude loading conditions. Furthermore, the fatigue life was predicted using Miner’s rule and Smith-Watson-Topper (SWT) criterion reaching reasonable results. 2. Experimental procedures A “dog bone” round specimens were used in the fatigue tests. These specimens were produced using a Renishaw machine model “AM400” operating at a scanning speed of 1.8 m/s, a layer thickness of 30 μ m, and a laser power of 350 W. The chemical composition of the feedstock material is according to the DIN 1706 (2021) standard and is detailed in Table 1. The specimens were produced in the vertical direction with layers oriented perpendicular to the loading direction, as shown in Figure 1.

Table 1. Chemical composition of the AlSI10Mg (%wt) (DIN 1706, 2021). Al Si Mg Mn Cu Ni Fe Zn Pb

Sn

Ti

Bal.

09-11

0.25-0.45

0.45 0.05

0.05

0.55

0.10

0.05

0.05

0.15

The specimens geometry is represented in Figure 1, and fatigue tests were conducted on a computer-controlled 100 kN DARTEC servo-hydraulic testing machine at room temperature under the load control mode using a sinusoidal wave at a frequency of 10 Hz. The variable loading amplitude spectrum was defined with three blocks, each having the same maximum stress and the same number of cycles (N = 2000 cycles) but with different stress ratios: R1=0, R2=0.5, and R3=0.25. To assess the notch sensitivity of the material under a variable loading amplitude, a semicircular notch was introduced around the surface, as depicted in Figure 1b).

Fig. 1. Specimens geometry: a) Unnotched and b) semicircular notch.