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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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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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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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Effect of Surface and Subsurface Defects on Fatigue Behavior of AlSi10Mg Alloy Processed by Laser Powder Bed Fusion (L-PBF)
摘要： The fatigue behaviour of an AlSi10Mg alloy processed by laser powder bed fusion (L-PBF) and subjected to different surface finishing processes was investigated paying special attention to the residual defects on the surface and the dominant fatigue failure mechanisms. Roughness measurements and qualitative surface morphology analysis showed smooth surfaces in the case of vibro-finishing and machining followed by polishing. The fatigue performance did not reveal to be directly related to surface roughness, but residual intrusions left on the finished surfaces. Post-mortem analysis showed single- or multiple-crack nucleation from pores opened on the surface, un-melted powders, or spatters considered as typical L-PBF defects. A fatigue limit of 195 MPa for machined and polished samples was obtained by substantial removal of surface and subsurface defects.
关键词： surface texture,laser powder bed fusion,AlSi10Mg alloy,surface finishing,fatigue strength
更新于2025-09-11 14:15:04
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Study on magnetic abrasive finishing of AlSi10Mg alloy prepared by selective laser melting
摘要： Selective laser melting (SLM) technology is playing an increasingly important role in today’s manufacturing industry. However, the surface quality of SLM samples is relatively poor and cannot be directly applied to industrial production. Therefore, this paper focuses on the post-treatment process of SLM AlSi10Mg alloy. First, the rough machining is performed by a grinding process (GP), and then, the magnetic abrasive finishing (MAF) is used for finish machining. The experiment results show that the combination of GP and MAF can effectively reduce the surface roughness and improve the surface quality of SLM AlSi10Mg alloy. The GP reduced the surface roughness to drop from 7 μm (after SLM forming) to about 0.6 μm, and the rough surface with defects such as spheroids and pits evolved into the fine surface with scratches and pores. The MAF reduced the surface roughness to a minimum of 0.155 μm, which resulted in excellent surface morphology. The surface hardness after the GP was higher, and the MAF reduced the hardness of the GP surface.
关键词： Grinding process,Hardness,AlSi10Mg alloy,Selective laser melting,Surface roughness,Magnetic abrasive finishing
更新于2025-09-11 14:15:04