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Effects of Platform Pre-Heating and Thermal-Treatment Strategies on Properties of AlSi10Mg Alloy Processed by Selective Laser Melting
摘要： The AlSi10Mg alloy was processed by selective laser melting using both hot- and cold-build platforms. The investigation was aimed at defining suitable platform pre-heating and post-process thermal treatment strategies, taking into consideration the peculiar microstructures generated. Microstructural analyses, differential scanning calorimetry, and high-resolution diffraction from synchrotron radiation, showed that in the cold platform as-built condition, the amount of supersaturated Si was higher than in hot platform samples. The best hardness and tensile performance were achieved upon direct aging from cold platform-printed alloys. The hot platform strategy led to a loss in the aging response, since the long processing times spent at high temperature induced a substantial overaging effect, already in the as-built samples. Finally, the standard T6 temper consisting of post-process solution annealing followed by artificial aging, resulted in higher ductility but lower mechanical strength.
关键词： processing temperature,AlSi10Mg alloy,aging treatment,selective laser melting
更新于2025-11-21 11:18:25
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Properties of Laser Metal Fused AlSi10Mg Alloy Processed Using Different Heat Treatments; Eigenschaften einer lasergeschmolzenen AlSi10Mg-Legierung und Anwendung von verschiedenen W?¤rmebehandlungen;
摘要： The AlSi10Mg alloy was fabricated by Laser Metal Fusion (LMF) using different post processing conditions. Tensile and dilatometric specimens were obtained with longitudinal axis parallel to the building direction. A first set of samples was directly aged in the as-built state (AB), while a second batch underwent solubilization annealing (SA) at 540 °C for 60 min just before artificial ageing (AA) at 160 °C for 8 h. Solubilization caused the precipitation of Si particles, suppressed by the rapid solidification during SLM. Moreover, it caused partial recrystallization leading to a coarser microstructure. The ageing response was very different in the two cases, involving a higher starting hardness for the as-built material, showing a markedly higher hardness during the whole process. In the as-built material, isochronal ageing experiments carried out by differential scanning calorimetry showed the precipitation of Mg2Si particles beneath Si, while the same transformations were much less intense in the solubilized sample, due to the lower Si supersaturation. The ageing process raised the yield strength of about 20% compared to the AB material, slightly reducing the fracture elongation. The same alloy after SA+AA showed a strength 25% lower than the AB+AA material, while ductility significantly increased.
关键词： Solution annealing,Ageing,AlSi10Mg,Laser Metal Fusion
更新于2025-09-23 15:19:57
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Strategy of Residual Stress Determination on Selective Laser Melted Al Alloy Using XRD
摘要： Selective laser melting (SLM) is known to generate large and anisotropic residual stresses in the samples. Accurate measurement of residual stresses on SLM-produced samples is essential for understanding the residual stress build-up mechanism during SLM, while a dramatic fluctuation can be observed in the residual stress values reported in the literature. On the basis of studying the influence of surface roughness on residual stress measured using X-ray diffraction (XRD), we propose a procedure coupling XRD technique with pretreatment consisting of mechanical polishing and chemical etching. The results highlight that residual stresses measured using XRD on as-built SLM-produced samples with high surface roughness are significantly lower than those measured on samples with finished surface, which is due to the stress relaxation on the spiked surface of as-built samples. Surface distribution of residual stresses and the effect of scanning strategy were systematically investigated for SLM-produced AlSi10Mg samples. Microstructural morphology was observed at the interface between sample and building platform and was linked to the surface distribution of residual stresses. This procedure can help us accurately measure the residual stresses in SLM-produced samples and thus better understand its build-up mechanism during the SLM process.
关键词： X-ray diffraction (XRD),residual stresses,AlSi10Mg,selective laser melting,surface roughness
更新于2025-09-19 17:13:59
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Predicting the fatigue life of an AlSi10Mg alloy manufactured via selective laser melting by using data from Computed Tomography
摘要： A modelling strategy is proposed to evaluate the influence of defect morphology on the fatigue limit of additively manufactured Al alloys by: (i) obtaining an x-ray micro-computed tomography (μ-CT) 3D image of the material, (ii) computing the Equivalent Inertia Ellipse of each individual pore, (iii) modelling the influence of the defect on the fatigue limit through the DSG approach and, (iv) 3D mapping the criticality of each individual defect. For this fatigue study, an AlSi10Mg alloy was manufactured by selective laser melting using sub-optimal deposition parameters in order to produce large lack-of-fusion defects. After a T6 heat treatment, tension-compression fatigue tests, with R = -1, were conducted on specimens oriented with their loading axis either parallel or normal to the Z-axis of the additive manufacturing equipment. Two samples were characterised before μ-CT testing in order to characterise the initial 3D defect population. Each sample was fatigued step by step in order to determine the fatigue limit. The fracture surface was then carefully observed using a scanning electron microscope (SEM) in order to identify the critical defect in the initial μ-CT image. A comparison with the fatigue results led to the following conclusions: (i) when the longest axis of the defect is perpendicular to the load axis, modelling the defect as an equivalent inertia prolate ellipse gives better results (5 % error on the fatigue limit) than modelling it as a simple equivalent sphere (22 % error on the fatigue limit), (ii) the prolate ellipse is not relevant when the longest axis of the defect is oriented along the loading axis; in this case an oblate equivalent ellipse should be used, (iii) the concept of ‘size’ for a complex 3D shaped defect should be linked to the inertia and the loading, (iv) with this approach, surface defects are shown to be more critical than internal ones for fatigue life and, (v) a 3D defect criticality map of the entire sample can be plotted to provide visual feedback on which defects are the most critical for fatigue life.
关键词： AlSi10Mg alloy,defect morphology,selective laser melting,fatigue life,Computed Tomography
更新于2025-09-19 17:13:59
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Modeling of thermal behavior and microstructure evolution during laser cladding of AlSi10Mg alloys
摘要： An improved three-dimensional finite element model has been proposed for studying the thermal behavior and microstructure evolution during laser cladding of AlSi10Mg alloys. Different material properties between AlSi10Mg powders and AlSi10Mg alloys are distinguished from the experiment and theoretical calculation to provide more reliable material parameters for simulation. In order to investigate the melting and solidification process during the formation of cladding layers, a temperature selection judgment mechanism is established to simulate the evolution of AlSi10Mg powders from the powder state to melting state and alloy state. In addition, to simulate the complex thermal behavior associated with powder particles and the voids between particles, a simplified exponential attenuation model is used for correcting the heat source. A complex asymmetric heat source considering about the different material properties and laser absorptivity on both sides of the remelting zone is used for multi-track cladding process. By simulating the temperature distribution of molten pool, the improved FEM could be used to predict the geometric shape of cladding layers (ignoring the effect of melting flow) and the temperature history. The simulation results show that the heat tends to diffuse to the unmelted powder owing to the asymmetric heat source during multi-track cladding, which leads to the asymmetry of cladding layers along the width direction. Based on the results of the temperature field simulations and the solidification characteristics of AlSi10Mg powders, the temperature gradient (G), solidification growth rate (R), cooling rate (G*R) and G/R are investigated to predict the morphology and size of the solidification microstructure under different laser scanning parameters. The scanning speed mainly determines the cooling rate during the laser cladding process, which results in different microstructures. Higher scanning speed leads to higher cooling rate, corresponding to a finer microstructure. Coarse dendrites are generated at the bottom of the molten pool, while finer dendrites are formed at the top.
关键词： Simulation,Microstructure evolution,AlSi10Mg alloy,Laser cladding,Thermal behavior
更新于2025-09-16 10:30:52
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Research and Optimization of Surface Roughness in Milling of SLM Semi-Finished Parts Manufactured by Using the Different Laser Scanning Speed
摘要： The paper studies the potential to improve the surface roughness in parts manufactured in the Selective Laser Melting (SLM) process by using additional milling. The studied process was machining of samples made of the AlSi10Mg alloy powder. The simultaneous impacts of the laser scanning speed of the SLM process and the machining parameters of the milling process (such as the feed rate and milling width) on the surface roughness were analyzed. A mathematical model was created as a basis for optimizing the parameters of the studied processes and for selecting the sets of optimum solutions. As a result of the research, surface with low roughness (Ra = 0.14 μm, Rz = 1.1 μm) was obtained after the face milling. The performed milling allowed to reduce more than 20-fold the roughness of the SLM sample surfaces. The feed rate and the cutting width increase resulted in the surface roughness deterioration. Some milled surfaces were damaged by the chip adjoining to the rake face of the cutting tool back tooth.
关键词： face milling,surface roughness,AlSi10Mg,SLM
更新于2025-09-16 10:30:52
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Silver Electroless Finishing of Selective Laser Melting 3D-Printed AlSi10Mg Artifacts
摘要： Additive manufactured selective laser melting (AM-SLM) parts often need post-printing coatings. The current research presents a method for surface finishing of AM-SLM AlSi10Mg parts coated by electroless silver plating. Such coating can be applied as a decorative film on printed replicas of antique artifacts. For this purpose, silver was deposited for the first time on AlSi10Mg printed disk-shaped specimens and coins, making their appearance close to the original artifact. The silver was plated with and without adhesion-promoting silane self-assembled monolayers. Dimensions and mass measurements, pilling test, light microscopy, optical profilometer, SEM–EDS examination, XRD analysis, and FIB-SEM technique were applied to characterize the coated samples. The results displayed good silver quality with a satisfactory appearance. The roughness of the plated samples was slightly reduced as the thickness of the silver layer was increased. The developed coating can be adapted for different applications, including printed replicas of coins in museum exhibitions.
关键词： Surface coating,Selective laser melting,Additive manufacturing,AlSi10Mg alloy,Macro and microstructure,Electroless silver plating
更新于2025-09-16 10:30:52
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On the Effect of Part Orientation on Stress Distribution in AlSi10Mg Specimens Fabricated by Laser Powder Bed Fusion (L-PBF)
摘要： The freedom of design of AM products suffers from some limitations in case of powder bed metal processes, because AM part’s integrity is affected by the residual stress state that is a consequence of the thermal history during part fabrication. Aim of this work is to evaluate the effect of part orientation on stress distribution. Thus, flat samples of AlSi10Mg alloy built along different orientations are produced by means of laser powder bed fusion (L-PBF) process, also known as Selective Laser Melting (SLM). Then, the semi-destructive hole-drilling method is used to evaluate residual stresses beneath the surfaces of samples. The outcomes of the study can be exploited to define design rules in order to both minimize support structures and optimize the orientation of the part in the building volume.
关键词： Powder bed fusion,Residual stresses,Hole-drilling method,AlSi10Mg,Orientation
更新于2025-09-16 10:30:52
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Manufacture of the Transceiver Housing for an Active Phased Array Antenna with Built-In Cooling Channels by Selective Laser Melting
摘要： A cooled transceiver housing of an active phased array antenna is produced by 3D printing from aluminum, on the basis of selective laser melting (SLM). The housing walls contain cooling channels, whose geometry ensures effective heat transfer from the active electronic components of the transceiver and also permits the manufacture of high-quality samples on existing 3D printing systems and facilitates cleaning of the channels after printing. The housing is made of AlSi10Mg aluminum, with an acceptable content of closed pores (no more than 1%). Its physicomechanical properties correspond to those of regular aluminum alloys used in the traditional manufacturing technology for such components. This housing may be used in advanced radar systems. The research permits recommendations for further development of the technology.
关键词： cooling channels,3D printing,transceiver housing,active phased array antenna,AlSi10Mg aluminum
更新于2025-09-16 10:30:52
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Rapid Solidification and Non-equilibrium Phase Constitution in Laser Powder Bed Fusion (LPBF) of AlSi10Mg Alloy: Analysis of Nano-precipitates, Eutectic Phases, and Hardness Evolution
摘要： The non-equilibrium phase evolution during laser powder bed fusion (LPBF) of AlSi10Mg alloy is thoroughly characterized and analyzed by means of advanced electron microscopy and analytical simulation of rapid solidification phenomenon. The evolution of microstructural strengthening agents such as inter-cellular eutectic phase and intra-cellular precipitates is presented in correspondence with the local variation of cellular/dendritic solidification patterns within a typical melt pool. The eutectic phase exhibits two different morphologies: lamellar and fibrous. As with the cell size variation, the overall volume fraction of eutectic phase and the lamella spacing is shown to gradually decrease by moving away from the melt-pool boundary (MPB), i.e., through crossing over from a coarse to a fine cellular zone. The eutectic-free regions within the a-Al cells contain a large number density of nano-sized precipitates that are predominantly Si-rich and are either fully or semi-coherent with the Al matrix. The formation of nano-precipitates is linked to the increased (non-equilibrium) solubility limits of a-Al cells due to the rapid solidification effect. For the first time, we identify such nano-precipitates with non-equilibrium crystal structures and morphologies: ‘‘Spheres’’ and ‘‘Ellipsoids’’ with Face Centered Cubic (FCC), and ‘‘Plates’’ and ‘‘Needles’’ with a Diamond Cubic (DC) superlattice structure that emerges from within the Al matrix. The microstructure in the heat-affected zone (HAZ) right underneath the MPB exhibits an absence of cell boundaries and eutectic phases while consisting primarily of large Si-rich and Mg-rich precipitates. Finally, the local variation of nano-hardness across a solidified melt pool is shown to correlate well with the corresponding profile of microstructural refinement, i.e., exhibiting a minimum at the HAZ and a peak at around the melt-pool centerline. The findings here can significantly advance the state of knowledge for the strengthening behavior in an as-built LPBF-processed AlSi10Mg alloy.
关键词： hardness evolution,Laser Powder Bed Fusion,non-equilibrium phase evolution,eutectic phases,nano-precipitates,AlSi10Mg
更新于2025-09-12 10:27:22