## 1 Introduction
### Scope of the Study  
Therefore, Al alloys are among the most appropriate metallic materials for modulating their own physical properties in order to improve the structural and mechanical characteristics. The shorter lead time, reduced processing costs, lower specific weight, and greater availability on the current global market--compared to other alloys--constitute key points that the aeronautical sector considers in relevant strategic choices. In the context of seeking more suitable and innovative solutions for AM, in this article, the authors outline the recent findings on a novel Al alloy tailored for the powder bed fusion-laser beam (PBF-LB) process. This study was conducted as part of the MANUELA (Additive Manufacturing Using Metal Pilot Line) project funded by the European Union's Horizon 2020 (grant agreement no. 820774); the material used was forAM(r) Al-HS1, which was developed for a PhD thesis in collaboration with Hoganas AB, Sweden [55; 56]. After a digression on the microstructural properties of this alloy and its mechanical characterization as a standard coupon, the prospective of the material in question is demonstrated at the subcomponent level for aeronautical applications. As already discussed in a previous paper [57], a hydraulic manifold for landing gear applications was used as an adequate benchmark to substantiate the applicability of AM technologies. Manifolds are actually devices with very complex geometries developed to withstand both steady and cyclic pressure loads; for their intricate design features, hydraulic fatigue is a crucial point because of the occurrence of abrupt right-angle turns and very small radii in the internal ducts, which can potentially lead to premature cracks. Considering this perspective, higher strength alloys, such as titanium or steel, are often preferred for these items [58; 59; 60]. Additionally, the repeated high cooling rates that the AM parts generally experience during fabrication affect the fatigue life due to the presence of treating defects (in particular, microporosity and surface roughness). The dfAM thermal operations encompass recurrent solid-state phase transitions, which introduce residual stress and a crystallographic texture, usually consisting in epitaxial grain growth along the building direction. On the other hand, the static mechanical properties of AM metals are considered quite comparable to metallic components manufactured conventionally. The advantages of AM with an emphasis on fatigue behavior were demonstrated for a COTS (commercial off-the-shelf) Al alloy (AlSi10 Mg) pursuing a typical step-by-step aeronautical qualification roadmap [57]. Herein, the authors highlight the huge potential of the novel high-strength Al alloys (Al-HS1 in particular) with respect to the same case study product; this activity allowed for enriching the experimental results with an in-depth characterization database. Following a typical building-block process, as shown in Figure 1, the new alloy, realized from a powder, was first characterized at the level of standardized coupons until its real validity was verified on a hydraulic subsystem for aeronautical interests (Figure 2). Figure 1: AM building blocks: the main steps toward the certification of parts. The existing components in AlSi10 Mg needed to be benchmarked, and, hence, it was considered important to compare these properties, even though the compositions of the materials are different. With respect to the standard AlSi10 Mg, the new alloy has superior static characteristics in the plasticization regime, with the ultimate strength and fatigue life limits being comparable. The optimized version of the manifold was designed by AIDRO, Italy; printed by Chalmers University of Technology, Goteborg, Sweden, using the EOS M290 LPBF machine (Krailling, Germany [61]); and analyzed and qualified by Magnaigh Aeronautica SpA, Italy. The qualification and certification processes demonstrate AM is still challenging and point to the extent its adoption for primary structural components.