## 2 Materials and Methods
### Conventionally and LMD-Manufactured Laves Phase Strengthened Ferritic Steel Materials  
In order to demonstrate the alloy development progress of HiperFer/HiperFer\({}^{\text{AM}}\)(Additive Manufacturing), we also investigated the predecessor alloy Crofer 22H. The conventional HiperFer material was vacuum induction melted by the Steel Institute of RWTH Aachen University, Germany. The ingots were hot rolled to 16 mm thickness at 920 \({}^{\circ}\)C and subsequently precipitation annealed (0.5-10 h/600-650 \({}^{\circ}\)C). Detailed information on the HiperFer steel grade is given in [18]. Conventionally manufactured Crofer22 H was supplied by VDM Metals GmbH, Unna, Germany. Crofer22 H [22; 23; 24] was recrystallized and additionally precipitation annealed at 0.5-10 h in the temperature range of 600 to 650 \({}^{\circ}\)C. The chemical compositions of conventional/LMD (laser metal deposition)-manufactured HiperFer/HiperFer\({}^{\text{AM}}\) are given in Table 3. The base HiperFer\({}^{\text{AM}}\) powder material was produced via gas atomization of an alloyed high purity Fe22 Cr alloy with argon gas. Elemental, high purity Si, Nb, and W powder materials were added to the Fe22 Cr powder and blended by mixing in a tubular mixing device (WAB GmbH) for 30 min by Fraunhofer ILT, Aachen, Germany.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter:** & **Value:** \\ \hline Layer thickness & 50 \(\upmu\)m \\ Laser power & 275 W \\ Exposure strategy & Stripes \\ Scan velocity & 760 mm/s \\ Hatch distance & 0.12 mm \\ Volume energy density & 60.3 J/mm\({}^{3}\) \\ Build rate & 13.5 cm\({}^{3}\)/h \\ \hline \hline \end{tabular}
\end{table}
Table 2: Laser powder bed fusion (LPBF) process parameters.  
Figure 2: (**a**) Semi-finished LPBF manufactured samples and (**b**) final compact tension specimens after electrical discharge machining (EDM).  
The experimental HiperFer\({}^{\rm AM}\) alloy was deposited on a steel substrate (AISI H10, 1.2365) by Fraunhofer ILT utilizing laser metal deposition. Specimens were manufactured on two five-axis handling systems, equipped with fiber-coupled diode laser systems LDM3000-60 (emitted wavelength: 976 nm; beam parameter product (BPP): 60 mm x mrad) and LDF2000-30 (emitted wavelengths 1025, 1064 nm; BPP: 30 mm*mrad) (Laserline GmbH, Mulheim-Karlich, Germany). For both machines, the optical alignment systems consisted of optical fibers with a core diameter of 600 \(\upmu\)m. For 3 mm beam diameter, a collimation lens (f\({}_{\rm c}\), 3 mm = 65 mm), followed by a focusing lens (f\({}_{\rm f}\), 3 mm = 230 mm) was applied. The smaller, 0.66 mm beam diameter was achieved via a combination of a collimation (f\({}_{\rm c}\), 0.66 mm = 200 mm) and a focusing lens (f\({}_{\rm f}\), 0.66 mm = 182 mm). The powder material was fed by pure argon carrier gas via a disc-based feeding system (Sulzer-Metco Twin 10C, OC Oerlikon AG, Pfaffikon, Switzerland) through a coaxial three-jet nozzle (Fraunhofer ILT). Shielding of the melt pool was achieved by argon shielding gas fed through the coaxial nozzle. The HiperFer\({}^{\rm AM}\) powder mixture was processed through applying the parameters listed in Table 4.