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CoCr alloy processed by Selective Laser Melting (SLM): effect of Laser Energy Density on microstructure, surface morphology, and hardness
摘要： Selective Laser Melting (SLM) was used to realize Co-28Cr-6Mo samples. Several process parameters were considered, resulting in a wide range of Laser Energy Density (LED). The study was focused on the investigation of both process and material-related aspects, such as surface morphology, laser tracks dimension and defects formation mechanisms. In addition, macro (HRC) and microhardness (HV0.5) was assessed. A correlation between LED value and density, surface quality, microstructural features and hardness of SLM parts was defined. The final goal was to identify, for the biomedical Co-28Cr-6Mo alloy, the optimal LED window to be considered in order to maximize the overall quality of SLM parts.
关键词： Additive Manufacturing (AM),Biomaterial,Selective Laser Melting (SLM),Laser Beam Melting (LBM),Co28Cr6Mo,Co-based alloys
更新于2025-09-19 17:13:59
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Characterisation of 17-4PH metallic powder recycling to optimise the performance of the selective laser melting process
摘要： The advantages of Additive Manufacturing (AM) processes are well known. Particularly, those AM techniques which are used to manufacture metallic parts are of great interest to industry due to the good mechanical behaviour of metallic alloys. Despite this, the quality of the manufactured parts is still an important issue due to the wide range of parameters that can affect them. In some powder bed fusion techniques, such as Selective Laser Melting (SLM), not all the initially distributed metallic powder is used in the process. There is an unmolten portion that can be recycled to ensure both the economic and environmental viability of the process. Even though this powder is unmolten, it is thermally affected due to the high temperatures attained during the process. This fact affects the powder properties and, consequently, the properties of the manufactured parts. Therefore, an analysis of the recycling effects of SLM metallic powders is an important issue in order to establish good recycling procedures and to optimise the process performance.
关键词： Additive manufacturing,17-4PH stainless steel,Powder bed fusion,Selective laser melting,Laser beam melting
更新于2025-09-16 10:30:52
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Laser beam melting of Cr3C2-NiCr
摘要： Due to the high temperature wear resistance, low friction coefficient and corrosion resistance, chromium carbides are widely used for coating applications and commonly processed through thermal spraying. In contrast to classical processing, additive manufacturing technologies such as Laser Beam Melting (LBM) offer significant geometrical flexibility in design. Relying on the use of this advantage for manufacturing innovative products, the present study focuses on the qualification of Cr3C2-NiCr for the LBM process. Experiments are carried out with composite thermal spray powder through variation of the main LBM process parameters and pre-heating temperatures up to 800 °C. Specimens are generated and evaluated with respect to material microstructure and mechanical properties. The results indicate that pre-heating can significantly improve the material quality. It prevents thermal cracking and substantially reduces porosity, in particular for low laser energy inputs. An impact of the LBM process parameters and pre-heating on the balance between the binder and the carbide phase is detected only for high laser energy inputs above 1000 J/mm3. Measurements of the micro-hardness of the laser molten material indicate a hardness close to the specifications of thermally sprayed material. A maximum transverse rupture strength around 600 MPa is achieved for specimens generated with pre-heating and medium laser energy inputs. For high laser energy inputs, secondary carbide and graphite phases occur inside the material microstructure.
关键词： Cutting tools,Additive manufacturing,Laser beam melting,Chromium carbide,Cr3C2-NiCr,LBM,Cermet
更新于2025-09-16 10:30:52
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Melt pool monitoring for laser beam melting of metals: inline-evaluation and remelting of surfaces
摘要： Laser Beam Melting of Metals (LBM-M) is an additive manufacturing technique that is applied successfully for the production of complex parts, small batch series and prototypes. In LBM metallic parts are generated layer by layer directly from sliced CAD data. For each layer a thin powder layer is deposited and subsequently irradiated by a focused laser beam which is guided by a galvanometer scanner. Due to variations in the powder stock, plain parameter sets and unresolved machine maturity problems, quality fluctuations are a major problem for a future series production. Surface roughness of parts during manufacturing is a quality issue. In this paper, we address it with a coaxial melt pool monitoring system and show a method for inline evaluation of surfaces by means of melt pool monitoring and the results of applied remelting strategies.
关键词： Laser Beam Melting,Additive Manufacturing,process stability,remelting,Selective Laser Melting,Melt pool Monitoring,Surface roughness,quality assurance
更新于2025-09-12 10:27:22
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Melt pool monitoring for laser beam melting of metals: assistance for material qualification for the stainless steel 1.4057
摘要： Laser Beam Melting of Metals (LBM-M) is an additive manufacturing technique that is successfully applied for the manufacturing of complex parts, small batch series and prototypes. In LBM metallic parts are generated layer by layer directly from sliced CAD data. For each layer a thin powder layer is deposited and subsequently, irradiated by a focused laser beam, which is guided by a galvanometer scanner. A major drawback of this relatively new manufacturing technology is a limited material portfolio. Today, the whole procedure of material qualification is time-consuming and resource intensive because a fast and reliable modelling of the process is not yet possible. In this work we are going to show the results of a qualification procedure applying a coaxial melt pool monitoring system to determine suitable processing parameters for a material, which has not yet been processed. In this work, a stainless steel material was exemplarily used to proof the feasibility. Furthermore, we are discussing the usability of this methodology for the material qualification in LBM-M in general.
关键词： Laser Beam Melting,Additive Manufacturing,Stainless Steel,Material Qualification,Quality Assurance,Selective Laser Melting,Process Stability,Melt pool Monitoring
更新于2025-09-12 10:27:22
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Laser beam melting process based on complete-melting energy density for commercially pure titanium
摘要： Laser beam melting (LBM) based on the complete-melting energy density for commercially pure titanium (CP-Ti) was investigated. Process parameters were set corresponding to the thermodynamically calculated energy density for full melting of CP-Ti. From the calculated energy density, power of 50–250 W and scan speed of 371–1855 mm/s were derived with the fixed other conditions. Microstructural study on formation of pores was conducted to understand the change in part’s density. Fundamental study with wide range of LBM process parameters, particularly based on the complete-melting energy density, could confirm the effects like high density and porous structure.
关键词： Laser beam melting,Complete-melting,Pure Ti,Energy density,Additive manufacturing
更新于2025-09-12 10:27:22
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Spatter formation during laser beam melting of AlSi10Mg and effects on powder quality
摘要： Cost and resource efficiency of Laser Beam Melting (LBM) highly depend on powder recycling procedures. Non-solidified powder can be sieved and reused in subsequent build cycles. However, due to quality concerns, powder recycling is not commonly practiced. One effect, which can impair the powder quality, lies in the formation and insertion of spatter particles during the melting process. In this paper, spatter particles emerging during LBM of AlSi10Mg are characterized regarding geometric (size, morphology), chemical (alloy composition, oxygen content, oxide layer thickness) properties as well as mass. Spatter particles are collected during the process using two isolation methods. Three types of spatter particles can be differentiated by their formation mechanism. It is found that spatter particles can differ significantly in oxide layer thickness and particle size. A significant share of spatter particles can be segregated by sieving. However, a certain fraction of the spatter particles will be included in the recycled powder.
关键词： Laser beam melting,AlSi10Mg,Powder recycling,Powder quality,Powder bed fusion,Powder reuse,Additive manufacturing,Reusability,Oxidation,Spatter
更新于2025-09-12 10:27:22
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3D grain growth simulation and experimental verification in laser beam melting of IN718
摘要： A predictive grain structure model originally used for selective electron beam melting (SEBM) is adapted to laser beam melting (LBM). Single lines with varying welding speeds were molten in a base plate made of polycrystalline IN718. The heat input is calculated with an analytical heat source model and the resulting melt pool geometry is compared with micrographs and high-speed camera shots. A typical welding microstructure is predicted by the grain growth model and confirmed with Electron Backscatter Diffraction (EBSD) measurements. With increasing line energies, a rising fragmentation of the grains is observed. This phenomenon is explained by an analyzation of the thermal gradients at the time of solidification of the grains.
关键词： additive manufacturing,laser beam melting,cellular automata,grain growth simulation
更新于2025-09-12 10:27:22
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Laser-induced plume investigated by finite element modelling and scaling of particle entrainment in Laser Powder Bed Fusion (LPBF)
摘要： Although metal vaporisation has been observed in several laser processes such as drilling or welding, vapour plume expansion and its induced side effects are not fully understood. Especially, this phenomenon is garnering scientific and industrial interest since recent investigations in Laser Powder Bed Fusion (LPBF) have designated metal vaporisation as main source of denudation and powder spattering. The present study aims to provide a new insight on the dynamics of laser-induced vaporisation and to assess the potential of different gases for particle entrainment. A self-consistent finite element model of laser-induced keyhole and plume is thus presented for this purpose, built from a comprehensive literature review. The model is validated with dedicated experimental diagnostics, involving high-speed imaging to measure the ascent velocity of the vapour plume. The transient dynamics of vapour plume is thus quantified for different laser incident intensities and gas flow patterns such as the mushroom-like structure of the vapour plume are analysed. Finally, the model is used as a tool to quantify the entrainment flow expected in LPBF and an analytical model is derived to define a velocity threshold for particle entrainment, expressed in term of background gas properties. Doing so it is possible to predict how denudation evolves when the gaseous atmosphere is changed.
关键词： metal vapour plume,laser beam melting (LBM),high-speed imaging,finite element modelling (FEM)
更新于2025-09-11 14:15:04
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Additive Manufacturing of Ku band Horn Antennas for Telecommunications Space Applications
摘要： This paper presents some recent achievements in the use of Metal Additive Manufacturing for horn antennas for space applications. Three prototypes of horn and cluster of horns are presented. Comparisons between simulations and measurements of RF performances are shown and some mechanical design to reduce mass are introduced. These new designs are possible thanks to the capabilities offered by Additive Manufacturing techniques.
关键词： Ku-band,Horn antenna,Additive Manufacturing,Laser Beam Melting
更新于2025-09-04 15:30:14