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The majority of aluminum alloys used for laser powder bed fusion are based on the aluminum-silicon system, particularly alloys containing 7 to 12 wt.% silicon and less than 1 wt.% magnesium. Silicon has a beneficial influence on melt viscosity during casting and laser additive manufacturing and prevents the formation of cracks. This study focused on the development of a new AlSi3.5Mg2.5 alloy for laser powder bed fusion with a Mg-Si content above 1.85 wt.% Mg 2 Si, which is the solubility limit of the α-aluminum matrix, and a subsequent heat treatment to adjust the mechanical properties with a wide range of strength and ductility values. The characterization of the microstructure was conducted by optical microscopy, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. The mechanical properties were determined by tensile tests and additional tight radius bending tests. The newly developed alloy was compared with AlSi10Mg and Scalmalloy ® . AlSi3.5Mg2.5 offers higher strength and ductility than AlSi10Mg, at comparable material costs. The mechanical properties can be adjusted in a wide range of values using a single step heat treatment. After direct ageing, the samples exhibited a ultimate tensile strength (UTS) of 484 ± 1 MPa and an elongation at break of 10.5% ± 1.3%, while after soft annealing, they exhibited a UTS of 179 ± 2 MPa and an elongation at break of 25.6% ± 0.9%.Metals 2020, 10, 514 2 of 13 coarsen [1,2]. Currently, there are only a few alternative processable aluminum alloys for additive manufacturing. These include casting alloys like AlSiCu alloys (EN AC-46xxx and EN AC-47xxx). These alloys offer high tensile strengths of up to 500 MPa with a low elongation at break of 5% [5][6][7].Many known alloys are difficult to process by laser powder bed fusion due to the formation of pores and cracks during solidification. These include medium and high strength wrought alloys of the alloy systems AlCu (EN AW-2xxx) [8][9][10], AlMgSi (EN AW-6xxx) [11,12], and AlZnMg (EN AW-7xxx) [13][14][15]. Known structural concepts for the development of alloys that are adapted to the additive manufacturing process use rare earth elements, such as scandium and zirconium, with varying content [16][17][18] or feature the addition of nanoscale grain refining additives to the known wrought alloys, such as the alloy EN AW-7075 [19]. When processed by laser additive manufacturing, both approaches lead to a combination with a high strength above 500 MPa combined with a good elongation at break of up to 15%. The disadvantages of these approaches are the high costs of scandium and the application of nanoparticles. A more detailed review of investigations into aluminum alloys for the LPBF process can be found in [20,21].The use of EN AW-6xxx alloys, whose strength is based on precipitation hardening, promises medium strength with a smaller decrease in ductility at low material costs. Artificial ageing leads to the formation of magnesium/silicon precipitates, which hinder dislocation mo...

Laser beam melting (LBM) of aluminum alloys is gaining a wide popularity in different industrial applications as an alternative technology for the production of individual and complex parts. A long build time and the high amount of experimental work for optimizing or finding new process parameters are two of the current challenges for reaching an industrial maturity. This paper proposes an efficient way to determine new process parameters for aluminum alloy aluminum‐silicon10‐magnesium with highest build‐up rates by using a 3D finite element model on the mesoscopic level. High laser power in combination with the hull‐core build strategy was used to increase the build‐up rate without impairing the part accuracy. The influences of high laser power, laser diameter and scan speed on the melt pool were studied by using a thermal simulation of single laser tracks. Based on the simulation results the process window could be derived and was tested on a laser beam melting (LBM) system. The achieved reduction of the build time of up to 31 % without loss in part accuracy proved the novel approach for the prediction of the required process window as an efficient method to reduce costly and time‐consuming experimental work.