## 3 Results and Discussion
### Results of the Analysis of HiperFer-17 Cr2
#### 3.2.2 High-Cycle Fatigue (HCF)  
The results obtained show a systematic effect of the HCF loading on the parameters derived from the eddy current and the incremental permeability analysis. As an example, Figure 9a illustrates the change in \(DZmax\) with an increasing number of HCF cycles (N) for all three temperatures, showing an increase in \(DZmax\) vs. \(N\). Corresponding to that, generally \(\epsilon_{a,p\text{-}intor.}\) decreases and \(HV10\) increases with the number of load cycles (see Figure 9b). From the 20 th cycle on, \(\left.\right|_{\mathit{EI}}\) \(\left.\right|\) shows minimal changes at 600 \({}^{\circ}\)C, but a slight decrease at 635 \({}^{\circ}\)C and 650 \({}^{\circ}\)C with increasing \(N\) (see Figure 9b). However, for the HCF loading, \(\epsilon_{a,p\text{-}intor.}\) and \(\left.\right|_{\mathit{EI}}\) \(\left.\right|\) show a strong correlation, i.e., a decrease with increasing \(N\), which indicates cyclic hardening.  
To illustrate the comparison and correlation of the 3 MA-X8 data with the mechanical measures, Figure 10 gives examples of the relationship between \(\left.\right|_{\mathit{EI}}\) \(\left.\right|\), \(\epsilon_{a,p\text{-}intor.}\) and \(HV10\) and different micromagnetic properties. For \(\left.\right|_{\mathit{EI}}\) \(\left.\right|\), at 650 \({}^{\circ}\)C, a correlation with \(DZmax\) can be observed, i.e., a decrease in \(DZmax\) with increasing \(\left.\right|_{\mathit{EI}}\) \(\left.\right|\) (see Figure 10a), while the  
Figure 9: Comparison of the 3 MA-X8 feature DZmax (**a**) with the mechanical features (**b**) as a function of the number of HCF cycles of HiperFer-17 Cr2.  
From Figure 12a and the results shown in [12], it is evident that there are considerable discrepancies in the precipitation density for the loaded conditions at the low temperature (600 \({}^{\circ}\)C) and higher temperatures (635 \({}^{\circ}\)C and 650 \({}^{\circ}\)C), i.e., a less pronounced precipitation occurs at 600 \({}^{\circ}\)C. Higher temperatures cause more pronounced precipitation due to enhanced diffusion processes, while recovery processes, especially regarding dislocation structure, are accelerated. In this context, it must be considered that the interaction between precipitates, dislocations and the domain walls is different depending on the precipitation structure. This introduces further complexity for accurate correlations between the microstructure and micromagnetic properties, which cannot be tackled using the limited database available so far.  
Since the evolution of the precipitation morphology differs depending on the temperatures, which influences the correlations, a reasonable correlation between precipitation density [12] and \(DZmax\) can be observed when each temperature is analyzed separately (see Figure 12a). It is noteworthy that the trend exhibits a different inclination at 600 \({}^{\circ}\)C compared to 635 \({}^{\circ}\)C and 650 \({}^{\circ}\)C. However, the current statistical database is insufficient for training separate models for each temperature. Therefore, the model is trained on the dataset containing data corresponding to all temperatures. The different trends of the 3 MA-X8 features for each temperature combined with the high potential for errors in the reference data result in unreliable outcomes (see Figure 12b).