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Ti6Al4V lattice structures manufactured by electron beam powder bed fusion - Microstructural and mechanical characterization based on advanced in situ techniques
(2022-12-17)
Powder bed fusion (PBF) processes enable the manufacturing of complex components in a time- and cost-efficient manner. Especially lattice structures are currently focused since they show varying mechanical properties, including different deformation and damage behaviors, which can be used to locally tailor the mechanical behavior. However, the present process-structure-property relationships are highly complex and have to be understood in detail in order to enable an implementation of PBF manufactured lattice structures ...
Aufsatz
Hydrogen absorption of ultra-high strength aluminum-silicon coated 22MnB5 steels
(2022-12-30)
The hot forming process allows to produce safety-relevant structural components in the automotive industry with strengths of 1500 MPa and higher. Generally, high strengths make material sensitive to hydrogen embrittlement. The heat treatment in the hot forming process chain is a potential source of diffusible hydrogen for hot-dipped aluminum-silicon coated boron-manganese steels. In the present work, the influence of different process gases and furnace dwell times during the heat treatment was investigated. Humidified ...
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Micromechanical Modeling of AlSi10Mg Processed by Laser-Based Additive Manufacturing: From as-Built to Heat-Treated Microstructures
(2022-08-13)
The unique microstructure of the alloy AlSi10Mg produced by the laser-based powder bed fusion of metals (PBF-LB/M) provides high-strength and high-strain-hardening capabilities of the material. The microstructure and mechanical properties of 3D-printed, i.e., additively manufactured, AlSi10Mg are significantly altered by post-building heat-treatment processes applied in order to tailor the final properties of the parts. Using an accurate computational model to predict and improve the mechanical performance of 3D-printed ...
Aufsatz
Microstructural Constituents and Mechanical Properties of Low-Density Fe-Cr-Ni-Mn-Al-C Stainless Steels
(2022-07-23)
Metallic material concepts associated with the sustainable and efficient use of resources are currently the subject of intensive research. Al addition to steel offers advantages in view of lightweight, durability, and efficient use of high-Fe scrap from the Al industry. In the present work, Al was added to Fe-12Cr-(9,12)Ni-3Mn-0.3C-xAl (x = 0.1–6) (wt.%) stainless steels to assess its influence on microstructure and mechanical properties. According to density measurements based on Archimedes’ principle, densities ...
Aufsatz
Investigation of processing windows in additive manufacturing of AlSi10Mg for faster production utilizing data-driven modeling
(2022-04-29)
To reduce production time and decrease production cost, the increase of layer thickness is an adequate option in powder bed fusion. In order to determine the relationships between process parameters in laser powder bed fusion (PBF-LB/M) and final porosity in AlSi10Mg, samples were processed following a space-filling experimental design in the present study. A total of 144 samples were fabricated considering layer thicknesses of 30 µm, 45 µm, 60 µm, and 90 µm. Afterwards, porosity was assessed using image analysis and ...
Aufsatz
On the Friction Stir Processing of Additive-Manufactured 316L Stainless Steel
(2022)
The novel combination of friction stir processing (FSP) and additive manufacturing (AM) is studied herein. Laser-based powder bed fusion of metals (PBF-LB/M) is used to establish 316 L stainless steel with a bimodal microstructure. Upon FSP, the as-built bimodal microstructure with an average grain size of 179 μm is transformed into the unimodal microstructure containing ultrafine grains with an average grain size of 1.2 μm. Results obtained by mechanical testing reveal that after FSP; the hardness, the yield point, ...
Aufsatz
Oxide Modified Iron in Electron Beam Powder Bed Fusion - From Processability to Corrosion Properties
(2022-03-07)
Additive manufacturing (AM) processes are not solely used where maximum design freedom meets low lot sizes. Direct microstructure design and topology optimization can be realized concomitantly during processing by adjusting the geometry, the material composition, and the solidification behavior of the material considered. However, when complex specific requirements have to be met, a targeted part design is highly challenging. In the field of biodegradable implant surgery, a cytocompatible material of an application-adapted ...
Aufsatz
Microstructural and mechanical properties of AlSi10Mg: Hybrid welding of additively manufactured and cast parts
(2022-12-07)
Welding and joining of hybrid components consisting of additively manufactured (AM) parts and conventionally processed parts offer new opportunities in structural design. In the present study, AlSi10Mg specimens were fabricated using two different manufacturing processes, i.e., laser-based powder-bed fusion of metals (PBF-LB/M) and casting, and welded by means of friction stir welding (FSW). Material strength of dissimilar welded joints was found to be governed by the as-cast material, which is characterized by a ...
Aufsatz
Additive Manufacturing of Binary Ni–Ti Shape Memory Alloys Using Electron Beam Powder Bed Fusion: Functional Reversibility Through Minor Alloy Modification and Carbide Formation
(2022-11-30)
Shape memory alloys (SMAs), such as Ni–Ti, are promising candidates for actuation and damping applications. Although processing of Ni–Ti bulk materials is challenging, well-established processing routes (i.e. casting, forging, wire drawing, laser cutting) enabled application in several niche applications, e.g. in the medical sector. Additive manufacturing, also referred to as 4D-printing in this case, is known to be highly interesting for the fabrication of SMAs in order to produce near-net-shaped actuators and ...
Aufsatz
Electrochemical polarization behavior and superelastic properties of a Fe–Mn–Al–Ni–Cr shape memory alloy
(2022-10-22)
The present study investigates the corrosion behavior of a Fe–Mn–Al–Ni–Cr shape memory alloy in a 5.0 wt% NaCl solution in combination with the functional properties. In a single crystalline condition, the investigated alloy shows a superior superelastic response with a maximum recovery strain of 5.2%. Furthermore, the results of the potentiodynamic polarization and impedance spectroscopy show that the addition of chromium generally improves corrosion resistance by increasing the resistance to localized corrosion. ...