- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
In-situ Measurements and Thermo-mechanical Simulation of Ti-6Al-4V Laser Solid Forming Processes
摘要： Residual stresses and distortions are two technical obstacles for popularizing the Additive Manufacturing (AM) technology. The evolution of the stresses in AM components during the thermal cycles of the metal depositing process is not yet clear, and more accurate in-situ measurements are necessary to calibrate and validate the numerical tools developed for its simulation. In this work a fully coupled thermo-mechanical analysis to simulate the Laser Solid Forming (LSF) process is carried out. At the same time, an exhaustive experimental campaign is launched to measure the temperature evolution at different locations, as well as the distortions and both the stress and strain fields. The thermal and mechanical responses of single-wall coupons under different process parameters are recorded and compared with the numerical models. Good agreement between the numerical results and the experimental measurements is obtained. Sensitivity analysis demonstrates that the AM process is significantly affected by the laser power and the feeding rate, while poorly influenced by the scanning speed.
关键词： Numerical simulation,Laser Solid Forming (LSF),Thermo-mechanical analysis,Additive manufacturing (AM),In-situ measurements of residual stresses
更新于2025-11-28 14:24:20
-
Cladding of Stellite-6/WC Composites Coatings by Laser Metal Deposition
摘要： This study aims to investigate the microstructure and hardness of multi-layered Stellite-6/WC metal-matrix composites coatings on metallic substrates cladded by laser metal deposition (LMD) for improvement of wear and corrosion resistances. As coating materials, Stellite-6 and WC-12wt.%Co powders were selected. Powder mixtures having various mixing-ratios of Stellite-6 and WC-12wt.%Co were provided vertically on S45C substrates by controlling powder feeding rates of the two powder feeders, individually. Stellite-6/WC composites which consist of three layers with different compositions were cladded on the S45C substrates by laser melting. Cross-sectional microstructure observation was carried out by using an optical microscope (OM). Vickers microhardness tests were conducted to evaluate hardness of the cladding layers and substrates. The experimental results demonstrate that hard multi-layered Stellite-6/WC metal-matrix composites coatings were successfully cladded on the S45C substrates. Property gradients in the Stellite-6/WC composites could be made due to the position-dependent chemical composition and microstructure made by controlling powder feeding rates of an LMD system.
关键词： Cladding,Additive Manufacturing (AM),Metal Matrix Composites (MMC),Laser Metal Deposition (LMD),Hard Materials
更新于2025-09-23 15:22:29
-
[IEEE NAECON 2019 - IEEE National Aerospace and Electronics Conference - Dayton, OH, USA (2019.7.15-2019.7.19)] 2019 IEEE National Aerospace and Electronics Conference (NAECON) - In Situ Process Monitoring for Laser-Powder Bed Fusion using Convolutional Neural Networks and Infrared Tomography
摘要： Additive Manufacturing (AM) is a growing field for various industries of avionics, biomedical, automotive and manufacturing. The onset of Laser Powder Bed Fusion (LPBF) technologies for metal printing has shown exceptional growth in the past 15 years. Quality of parts for LPBF is a concern for the industry, as many parts produced are high risk, such as biomedical implants. To address these needs, a LPBF machine was designed with in-situ sensors to monitor the build process. Image processing and machine learning algorithms provide an efficient means to take bulk data and assess part quality, validating specific internal geometries and build defects. This research will analyze infrared (IR) images from a Selective Laser Melting (SLM) machine using a Computer Aided Design (CAD) designed part, featuring specific geometries (squares, circles, and triangles) of varying sizes (0.75-3.5 mm) on multiple layers for feature detection. Applying image processing to denoise, then Principal Component Analysis (PCA) for further denoising and applying Convolution Neural Networks (CNN) to identify the features and identifying a class which does not belong to a dataset, where a dataset are created from CAD images. Through this automated process, 300 geometric elements detected, classified, and validated against the build file through CNN. In addition, several build anomalies were detected and saved for end-user inspection.
关键词： Laser Powder Bed Fusion (LPBF),Principal Component Analysis (PCA),infrared image (IR),Convolution Neural Networks (CNN),Additive Manufacturing (AM),Computer Aided Design (CAD)
更新于2025-09-23 15:21:01
-
Directed energy deposition of Al 5xxx alloy using Laser Engineered Net Shaping (LENS??)
摘要： Here, we present directed energy deposition (DED) of wrought-like Al 5xxx AlMg alloy by Laser Engineered Net Shaping (LENS?). A transition from an Al 5083 gas atomized powder feedstock to Al 5754 characteristics of the as-deposited material due to selective evaporation of Mg was observed. Density values obtained by X-ray micro-computed tomography (μ-CT) were compared to those obtained by the Archimedes method. The latter indicated a relative density as high as 99.26%. Possible origins of porosity are discussed. The as-deposited material was comprised of both equiaxed and columnar grains with no preferred crystallographic orientation and mean grain size of 36 μm. The Young's modulus, yield stress, ultimate tensile strength, fracture strain, Poisson's ratio, and total ultimate strain energy (toughness) were determined by uniaxial tensile tests combined with digital image correlation (DIC). Fractography complemented the mechanical testing. A pulse-echo ultrasonic non-destructive test was used to obtain more accurate values of the Young's and shear moduli and to adjust the value of the yield strength accordingly. The measured mechanical properties meet the requirements of international standards for wrought Al 5754 in its annealed condition.
关键词： Additive manufacturing (AM),Mechanical properties,Micro-computed tomography (μ-CT),Laser Engineered Net Shaping (LENS?),Directed energy deposition (DED),Aluminum alloys
更新于2025-09-23 15:21:01
-
Crystallographic Orientation Control of 316L Austenitic Stainless Steel via Selective Laser Melting
摘要： In recent years, additive manufacturing has attracted attention as a technology that enables control of the crystallographic texture of metallic materials. We achieved successful control of the crystallographic texture of 316L austenitic stainless steel using selective laser melting (SLM). Three distinguished textures were achieved by changing the laser scan speed, namely: the single crystalline-like texture with {001} orientation in the build direction, the crystallographic lamellar texture in which two kinds of grains with {011} and {001} orientations in the build direction are alternately stacked, and polycrystalline with relatively random orientation. The melt pool shape and the solidification behavior (thermal gradient and migration velocity of solid/liquid interface) in a melt pool could be important controlling factors for the evolution of the crystallographic texture under the SLM process.
关键词： anisotropy,crystallographic texture,metal additive manufacturing (AM),selective laser melting (SLM),melt pool
更新于2025-09-23 15:19:57
-
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
-
Laser welding of AlSi10Mg aluminium-based alloy produced by Selective Laser Melting (SLM)
摘要： Additive manufacturing can produce very complex and highly integrated parts that cannot be manufactured by traditional methods. In many of its applications, the AM-manufactured part may be a very small part of the whole, and therefore it has become increasingly important to find suitable attachment methods for printed parts. The aim of this study was to find out the laser weldability of the printed AlSi10Mg material without filler material. The laser used in these welding experiments was Yb:YAG disk laser. The laser wavelength was 1030 nm and the maximum output power on the workpiece surface was 4 kW. AlSi10Mg is a widely used material in parts that are produced utilizing the SLM technique. The material has very good corrosion resistance properties, good electrical conductivity and excellent thermal conductivity. AlSi10Mg has proven to be much easier to print than steel materials, so it is a popular material also in prototype production. Based on welding tests, laser welding without filler material is suitable for AlSi10Mg material and the static strength of the weld is reasonably good compared to the base material. However, AlSi10Mg can be found to be challenging due to its composition.
关键词： Selective Laser Melting (SLM),AlSi10Mg,Yb:YAG disk laser,Laser welding,Additive Manufacturing (AM)
更新于2025-09-12 10:27:22
-
Disk Laser Assisted Surface Heat Treatments Of AlSi10Mg Parts Produced By Selective Laser Melting (SLM)
摘要： Metal parts produced with the Selective Laser Melting (SLM) method have a great variety of uses today and because of this the requirements on the surface quality differ between applications. The surface treatments of the printed metal pieces, like other finishing phases, are often still manually worked on and thus are very time-consuming processes. This study focuses on the SLM printed AlSi10Mg aluminium specimen’s surface laser heat treatment with disk laser equipment (wavelength of 1030nm). The goal of this study was to achieve the desired effect on the aluminium’s surface quality with robotized laser heat treatment equipment. This was to show that the used finishing treatment method could be automated or robotized. The study showed that with the correct laser parameters, it is possible to generate desired effects and features on to the AlSi10Mg aluminium piece’s surface with a robotized process.
关键词： Selective Laser Melting (SLM),laser forming,AlSi10Mg,Additive Manufacturing (AM)
更新于2025-09-12 10:27:22
-
Effect of Hot Isostatic Pressing on Al-10%Si-0.4%Mg Alloy Fabricated by Selective Laser Melting; レーザ積層造形により作製したAl-10%Si-0.4%Mg合金における熱間等方加圧処理の影響;
摘要： In this study, we investigated the effects of hot isostatic pressing (HIP) on the mechanical properties of an Al-10%Si-0.4%Mg alloy fabricated by selective laser melting (SLM). In addition, the effect of internal porosity on the mechanical properties of the alloy was also investigated. After the HIP, the internal porosity of the alloy decreased, while its elongation to failure (EL) improved significantly. However, the 0.2% proof stress (PS) and the tensile strength (TS) of the HIPed alloy were significantly lower than those of the as-built state. This can be attributed to the microstructural changes that occurred at elevated temperatures during the HIP. In addition, the PS and TS of the as-built alloy decreased with an increase in the internal porosity. On the other hand, in the case of the HIPed alloy, the PS and TS were not affected by the internal porosity. However, EL was sensitive to the internal porosity. The EL of the HIPed alloy decreased with an increase in its initial internal porosity. This is because the diffusion bonding during the HIP was imperfect owing to the presence of oxidized scales. Hence, it is imperative to optimize the laser irradiation conditions for the fabrication of aluminum alloy by SLM.
关键词： aluminum alloy,selective laser melting (SLM),hot isostatic pressing (HIP),additive manufacturing (AM),internal porosity
更新于2025-09-11 14:15:04