PSI - Issue 38

Alexander Raßloff et al. / Procedia Structural Integrity 38 (2022) 4–11 A. Raßlo ff et al. / Structural Integrity Procedia 00 (2021) 000–000

10

7

(a) ˜ s δ = 1 , φ = 0 . 325 %

˜ s esd

0 . 9 1 . 2 Rel. ranking parameter ˜ P 1 . 0 1 . 1

40

0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

30

20

10 Gamma PDF

0

0 . 6 0 . 7 0 . 8 0 . 9 1 . 0 1 . 1 1 . 2 1 . 3 1 . 4 Relative scale parameter of ESD distribution ˜ s esd

50 100 ESD d eq in µ m

(b) ˜ s esd = 1 , ˜ s δ = 1 , φ = 0 . 25 %

(c) ˜ s esd = 1 , ˜ s δ = 1

0 . 7 1 . 0 Rel. ranking parameter ˜ P 0 . 8 0 . 9

1 . 0 1 . 3 Rel. ranking parameter ˜ P 1 . 1 1 . 2

80

100

120

140

0 . 2

0 . 4

0 . 8

60

0 . 6

√ area of largest pore in µ m

Porosity φ in %

˜ P FS

˜ P APS

˜ P MPS

˜ P √ area

Fig. 6. Relative ranking parameters ˜ P from simulations and empirical estimations.

are more larger pores compared to small values. This result seems plausible as larger pores tend to have a major impact on the fatigue performance. The empirical ranking parameter ˜ P √ area remains fairly constant for ˜ s esd ≥ 0 . 8, indicating that the size of the largest pore does not change significantly. However, the FIP based parameters suggest a further decreasing trend, underlining the potential of high-resolution CP simulations, allowing for a more sophisticated investigation. The data in Figure 6(b) shows the defined trend of ˜ P √ area . The other parameters pose significant scatter. ˜ P FS and ˜ P APS even rise for pores below √ area = 100 µ m. That could imply a less pronounced impact of the largest pore com pared to other factors related to local phenomena. This relation seems to change as the ranking parameters decrease for higher √ area. The study on the influence of the porosity shows the expected outcome of worse fatigue performance for higher porosity. It can be seen from Figure 6(c) that the empirically motivated parameter follows roughly the same trend. The cause could lie in the increased possibility of larger pores for higher volume fraction of pores.

4. Conclusion

An experimental-numerical analysis of microstructure-property relationships for AM materials is presented at the example of the influence of pores on the fatigue behaviour. These relationships are derived by (a) manufacturing specimen of Ti-6Al-4V, (b) characterising their microstructure by LM and CT, (c) computing meaningful structural