## 3 Results and Discussion
### Results of the Analysis of HiperFer-17 Cr2
#### 3.2.1 Low-Cycle Fatigue (LCF)  
Figure 5 illustrates the correlation between one of the 3 MA-X8 features (_DZmax_) and the number of LCF cycles, excluding the initial state and the changes occurring in the first 10 cycles. The LCF loading from 10 to 2000 cycles of HiperFer-17 Cr2 causesmacroscopic/wide-ranging changes in the microstructure and the mechanical properties, which correlate with changes in the magnetic properties. The mechanical properties exhibit significant changes across varying load cycles: a notable increase in mechanical hardness is observed, ranging from 190 to 280 _HV10_, depending on the loading temperature, over a span of 10 to 2000 load cycles. Additionally, \(\varepsilon_{\textit{a,p-inter. }}\) decreases with an increasing number of load cycles, indicating a cyclic hardening, which is mainly driven by Laves phase precipitation and corresponds to the rise in _HV10_ and partially corresponds to a decrease in \(\mid\!\varepsilon_{\textit{II}}\!\mid\). Note that previous work indicates that \(\mid\!\varepsilon_{\textit{II}}\!\mid\) is more sensitive to changes in the precipitation state than _HV10_ or \(\varepsilon_{\textit{a,p-inter. }}\)[14; 16], which might explain the deviations in the evolution of \(\mid\!\varepsilon_{\textit{II}}\!\mid\)[12]. During the first cyclic saturation phase, the microstructural changes are only weakly pronounced and substantial Laves phase precipitation sets in after this phase. This is reflected in the change in magnetic properties presented in Figure 5a. During the final cyclic hardening, thermo-mechanical-induced precipitates form, resulting in pronounced cyclic hardening and in a change in the magnetic properties. As the formation of the precipitates is initiated earlier at higher temperatures, the change in the magnetic behavior starts earlier. It can be observed that the magnetic behavior significantly changes once the formation of the precipitates starts, which corresponds more or less with the change in \(\varepsilon_{\textit{a,p-inter. }}\) (Figure 5). Since a qualitative correlation between the microstructural changes, the mechanical properties and the magnetic measurements is observed, manual correlations of the 3 MA-X8 measurements with the mechanical properties are conducted to identify outliers, to recognize trends and to explore initial correlation possibilities. Most of the 3 MA-X8 features that show a good correlation with the mechanical properties are derived from the incremental permeability and eddy current analysis, indicating that the significant systematic change in the material properties takes place near the surface. In Figure 6, some examples of correlations between the mechanical measures, i.e., \(\mid\!\varepsilon_{\textit{II}}\!\mid\), _HV10_ and \(\varepsilon_{\textit{a,p-inter. }}\), and the micromagnetic features are presented, being representative for all of the correlations determined. The hardness _HV10_ and plastic strain amplitude \(\varepsilon_{\textit{a,p-inter. }}\) show a strong correlation with the micromagnetic properties for all temperatures (see examples in Figure 6b,c), whereas a clear correlation between the 3 MA-X8 features and the cyclic hardening potential \(\mid\!\varepsilon_{\textit{II}}\!\mid\) is observed only for one temperature, which is exemplarily shown for _W3Z_ in Figure 6a. However, it shows no systematic trend when considering the results obtained at the other temperatures. As clear trends in the changes  
Figure 5: Comparison of (**a**) the 3 MA-X8 feature _DZmax_ with (**b**) the mechanical features as a function of the number of LCF cycles for HiperFer-17 Cr2. in \(\mid e_{II}\mid\) are only obtained at 650 \({}^{\circ}\)C, a correlation with the micromagnetic measurements is only possible for this temperature. However, the microstructural reasons for this remain unclear and need to be analyzed in future work.