Effects of Power and Laser Speed on the Mechanical Properties of AlSi7Mg0.6 Manufactured by Laser Powder Bed Fusion (original) (raw)
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Materials Science and Engineering: A
Additively manufactured (AM) products use two scanning strategies to create the central core region and the inner region near the free-surface circumference i.e. the shell. Manufacturers usually machine the shell to meet standard mechanical property testing. However, it’s essential to determine how the shell affects an AM product’s mechanical properties. This study focused on the dynamic tension and compression mechanical properties of an AlSi10Mg alloy made using the laser powder bed fusion technique. Machined and non-machined samples with and without shells of different build sizes and orientations underwent testing using split Hopkinson bar systems. Machined products displayed anisotropic dynamic behavior, favoring vertically built samples for maximum dynamic stress and horizontally built samples for elongation. However, samples with a shell showed apparent isotropic dynamic behavior due to pore distribution in the shell regime. The high porosity in the shell region resulted from the high intensity of heating energy input during scanning. Differences in shell shape between Z (load parallel to the direction of the building) and XY (load tangential to the direction of the building) samples and a slower, repeated laser scanning process in the shell region contributed to differences in porosity distribution between orientations. High porosity negatively impacted mechanical behavior and reduced dynamic mechanical properties.
Materials & Design, 2021
Themain drawback of laser powder bed fusion (L-PBF), commonly called selective lasermelting (SLM) is the high porosity which may lead to an early failure of the parts. To minimize it, the L-PBF parameters need to be optimized focusing on the laser power, scanning speed and hatching space. However, no standard guideline exists. In this study, an efficient and cost-effective methodology is developed and validated on AlSi12. This innovative methodology brings together single scan tracks (SST),macroscopic properties analysis and design of experiments (DOE). It requires three batches of SST, cubes and tensile samples. The DOE significantly decreases the manufacturing and characterization costs. 9 SST are sufficient to identify a process window that is 85% similar to the one obtained froma full factorial designwith 105 SST. This process windowreliably leads to high densities and better mechanical properties in comparison to the state-of-the-art properties reported in the literature for L-PBF AlSi12. In conclusion, a methodology using only 9 SST, 18 cubes and 12 tensile tests has been validated on AlSi12. It is further envisioned to optimize the L-PBF parameters of any existing or new alloy leading potentially towards better mechanical properties than the state-of-the-art in the literature.
Materials, 2022
Laser powder bed fusion (L-PBF) is an additive manufacturing technology that is gaining increasing interest in aerospace, automotive and biomedical applications due to the possibility of processing lightweight alloys such as AlSi10Mg and Ti6Al4V. Both these alloys have microstructures and mechanical properties that are strictly related to the type of heat treatment applied after the L-PBF process. The present review aimed to summarize the state of the art in terms of the microstructural morphology and consequent mechanical performance of these materials after different heat treatments. While optimization of the post-process heat treatment is key to obtaining excellent mechanical properties, the first requirement is to manufacture high quality and fully dense samples. Therefore, effects induced by the L-PBF process parameters and build platform temperatures were also summarized. In addition, effects induced by stress relief, annealing, solution, artificial and direct aging, hot isost...
Fracture resistance of AlSi10Mg fabricated by laser powder bed fusion
Acta Materialia, 2021
The combination of refined microstructures (induced by rapid cooling) and melt pool-induced mesostructures in AlSi10Mg fabricated using laser powder bed fusion (LPBF)-a widely used additive manufacturing technique-impart high strength and fracture toughness. Further exploitation of such property combinations requires a detailed understanding of how the processing conditions control the micro-and mesostructures and, in turn, the mechanical performance, especially regarding fracture resistance. Towards this end, the crack resistance curve (R-curve) behavior in different orientations of LPBF-fabricated AlSi10Mg alloys processed with different layer thickness, hatch spacing, and scan strategies was evaluated and correlated with micro-and mesostructural features such as grain size and grain orientation, texture, cell morphology, and melt pool arrangement. Results show a strong anisotropy in both tensile stressstrain behavior and fracture toughness with layer thickness and hatch spacing controlling strength and scan strategy dictating fracture resistance. In terms of tensile stress-strain behavior, the arrangement of melt pool boundaries with respect to loading direction results in anisotropy in ductility whereas strength is controlled by grain size and cellular structure. In case of fracture toughness, measurements show that failure is dominated primarily by melt pool morphology and hence the mesostructure that is controlled by scan strategy. They furthermore reveal, that, despite the pronounced anisotropy in the R-curve behavior the presence of such mesostructure enables a level of damage-tolerance in AlSi10Mg that cannot be achieved in a cast alloy.
Discover Materials
In recent years, there has been a growing interest in the use of additive manufacturing (AM) to fabricate metallic components with tailored microstructures and improved mechanical properties. One of the most promising techniques for the aerospace industry is powder bed fusion-laser beam (PBF-LB). This technique enables the creation of complex shapes and structures with high accuracy and repeatability, which is especially important for the aerospace industry where components require high precision and reliability. However, the impact of the PBF-LB process on microstructural features, such as the grain size distribution and porosity, remains an important area of research since it influences mechanical properties and performance of materials. In this study, a multimodal and multiscale correlative microscopy approach is used to investigate the microstructure of AlSi10Mg components made by PBF-LB. The study found that the correlative microscopy approach involving X-ray images with visual...
SELECTIVE LASER MELTING PROCESS OPTIMIZATION AND MECHANICAL PROPERTIES EVOLUTION OF ALSI10MG
IAEME PUBLICATION, 2024
Unlike conventional methods that involve removing components from a product, the groundbreaking idea behind additive manufacturing (AM) is the gradual creation of materials. A computer-controlled laser is often used in additive manufacturing to shape and consolidate powder feedstock in a layer-by-layer fashion to arbitrary shapes. The aerospace, defense, automotive, and biomedical sectors have high standards, and AM is now being refined to create complex-shaped functional metallic components out of metals, alloys, and other materials. Lightweight structural components with series similar mechanical characteristics may be produced using Selective Laser Melting (SLM), one of the AM technologies that eliminates the requirement for part specific tooling or downstream sintering procedures, among other things. The low weight and excellent mechanical and chemical qualities of aluminium make it an ideal material for such environmentally designed components. We need further information on how processing circumstances and material qualities affect the microstructural and mechanical properties of AM produced components as well as the metallurgical processes that produce them. Following this, we provide a comprehensive overview of AM's material and process components, including the mechanical and microstructural features of AM-processed parts as well as the physical characteristics of AM-optimized materials. Ultimately, the samples made using SLM-Alsi10Mg demonstrated an ultimate tensile strength of 150 MPa, yield strength of 120 MPa, and an elongation of 20%, as determined by the testing data. Mechanical properties of AlSi10Mg, additive manufacturing, laser powder bed fusion, selective laser melting, and related terms.
Materials Science and Engineering: A, 2020
AlSi7Mg0.6 alloy is widely used in the automotive and aeronautical industries, and metal additive manufacturing (AM) is a breakthrough technology that motivates foundry companies to explore its potential in these industries; however, there is no deep knowledge of the mechanical properties and their relationship to microstructure in parts obtained by selective laser melting (SLM), as there is for parts obtained by casting. In this work, a comparison of the microstructure and mechanical properties of AlSi7Mg0.6 alloy obtained by SLM and investment casting processes was made. The mechanical properties of tensile specimens processed by both technologies were evaluated by uniaxial tensile tests and microhardness measurements in as-built/as-cast and heat-treated conditions with different build orientations in the case of SLM. An advanced characterization of the microstructure by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD) analysis was also performed. After analyzing the microstructure and mechanical properties obtained with different heat treatments, the strengthening mechanisms of the two processes were identified. It is possible to obtain improved mechanical properties with SLM processing, exceeding the typical values required for aeronautical parts obtained in investment casting heat-treated (T6), and the ductility is satisfactory. Direct aging after SLM processing can effectively strengthen the AlSi7Mg0.6 alloy and is the more effective way to improve the as-built mechanical properties.
Journal of Alloys and Compounds, 2020
The components produced by laser powder bed fusion (LPBF) generally require specific heat treatments in order to release the residual stresses induced during the additive manufacturing process. Postprocessing treatments also play a significant role in obtaining components whose microstructure and characteristics are homogeneous and tailored for specific applications. A comparison of the mechanical features resulting from different heat treatments requires that a material showing the same initial mechanical features and microstructure is investigated. In the present work the effects of a number of different thermal post-processing treatments are compared: AlSi10Mg parts processed by LPBF underwent various thermal treatments such as stress relieving, annealing at high temperature and T6 treatments. The microstructure variation as a function of the applied temperature was correlated to the material mechanical behaviour in term of hardness and tensile strength; impact properties were also evaluated. The thermal evolution of the system was then studied through differential scanning calorimetry and x-ray diffraction analyses.