PSI - Issue 53

Luca Marchini et al. / Procedia Structural Integrity 53 (2024) 203–211 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Figure 3b shows the same thickness loss data plotted against the square root of immersion time. The data fitting with the parabolic relationship x=kt 0.5 (where “k” is growth constant, “ Δ x” is the loss of thickness and “t” is the time) is quite good. This confirms that the consumption of steel samples was controlled by diffusion processes, which is reasonable considering the relative long exposure times (Dangi et al. , 2018).

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b)

Figure 3– (a) Thickness loss Vs the immersion time and (b) thickness loss Vs the square root of immersion time

Despite the samples exhibit similar parabolic dissolution-time relationship, the AM maraging steel one displays a dissolution pattern that is notably more homogeneous in comparison with the forged counterpart (Fig. 4). This difference may be the consequence of the different corrosion kinetics of the samples in contact with molten Al. However, it is also plausible that the irregular corrosion pattern observed on forged samples is related to their characteristic segregation bands, as highlight in Figure 4c, compared to the more uniform and finer microstructure characteristic of AM samples.