scholarly journals Laser Finishing of Ti6Al4V Additive Manufactured Parts by Electron Beam Melting

2019 ◽  
Vol 10 (1) ◽  
pp. 183
Author(s):  
Silvio Genna ◽  
Gianluca Rubino
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Continuous Wave ◽  
Laser Energy ◽  
Three Dimensional ◽  
Surface Finishing ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Reduced Surface

In this work, the feasibility of laser surface finishing of parts obtained by additive manufacturing (AM) was investigated. To this end, a 450 W fiber laser (operating in continuous wave, CW) was adopted to treat the surface of Ti-6Al-4V samples obtained via electron beam melting (EBM). During the tests, different laser energy densities and scanning speeds were used. In order to assess the quality of the treatment, either the as-built or the treated samples were analyzed by means of a three-dimensional (3D) profilometer, digital microscopy, and scanning electron microscopy. Analysis of variance (ANOVA) was performed to check which and how process parameters affected the finishing. The results show that, in the best conditions, the laser treatment reduced surface roughness by about 80%.

scholarly journals Electron beam melting in the fabrication of three-dimensional mesh titanium mandibular prosthesis scaffold

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Rongzeng Yan ◽  
Danmei Luo ◽  
Haitao Huang ◽  
Runxin Li ◽  
Niu Yu ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Three Dimensional

scholarly journals Three-Dimensional Nano-Morphology of Carbon Nanotube/Epoxy Filled Poly(methyl methacrylate) Microcapsules

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1387 ◽  
Author(s):  
M. Galip Icduygu ◽  
Meltem Asilturk ◽  
M. Akif Yalcinkaya ◽  
Youssef K. Hamidi ◽  
M. Cengiz Altan
Keyword(s):  
Confocal Microscopy ◽  
Methyl Methacrylate ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Poly Methyl Methacrylate ◽  
Scanning Confocal Microscopy ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Average Size

The three-dimensional nano-morphology of poly(methyl methacrylate; PMMA) microcapsules filled with carbon nanotubes (CNTs) and epoxy resin were investigated by various microscopy methods, including a novel, laser scanning confocal microscopy (LSCM) method. Initially, PMMA microcapsules containing various amounts of CNTs were synthesized by a solvent evaporation method. Scanning electron microscopy analysis showed that pore-free, smooth-surface microcapsules formed with various types of core-shell morphologies. The average size of CNT/epoxy/PMMA microcapsules was shown to decrease from ~52 μm to ~15 μm when mixing speed during synthesis increased from 300 rpm to 1000 rpm. In general, the presence of CNTs resulted in slightly larger microcapsules and higher variations in size. Moreover, three-dimensional scans obtained from confocal microscopy revealed that higher CNT content increased the occurrence and size of CNT aggregates inside the microcapsules. Entrapped submicron air bubbles were also observed inside most microcapsules, particularly within those with higher CNT content.

scholarly journals The Influence of Neodymium Element on the Crater Structure Formed on Al-17.5Si Alloy Surface Processed by High-Current Pulsed Electron Beam

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 922
Author(s):  
Kui Li ◽  
Bo Gao ◽  
Ning Xu ◽  
Yue Sun ◽  
Vladimir Viktorovich Denisov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Primary Silicon ◽  
Structural Defects ◽  
Metallic Materials ◽  
High Current ◽  
Metallic Material ◽  
Pulsed Electron Beam ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

The effect of neodymium element on the elimination of crater structures on the surface of Al-17.5Si metallic materials processed by high-current pulsed electron beam was investigated in this study. Field emission scanning electron microscopy analysis indicated that the grain sizes of Al-17.5Si metallic materials were reduced and craters were removed from surfaces of the processed Al-17.5Si metallic material after addition of Nd. This can be attributed to the efficient transfer of heat accumulated in rich-silicon (primary silicon) areas without the eruption of a primary silicon phase if the size of primary silicon grains are small. The X-ray diffraction analysis indicates that all diffraction peaks are broadened because of the presence of structural defects, grain refinement and stress state. Electron probe micro-analyzer analysis demonstrated that Al and Nd were evenly distributed on the surface of the treated alloy, which could be attributed to the diffusion of the element. Transmission electron microscopy analysis showed that nano-Al and nano-Si cellular textures were generated during the treated process. The formation of these structures can be attributed to rapid heating and cooling effects by the treatment. Finally, electrochemical tests revealed that the corrosion current density of Al-17.5Si metallic materials (with Nd, 0.3 wt.%.) surface decreased by three orders of magnitude compared with that of the processed Al-17.5Si metallic material surfaces (without Nd). This can be attributed to the elimination of craters and grain refining.

scholarly journals Validation experiments for LBM simulations of electron beam melting

2014 ◽  
Vol 25 (12) ◽  
pp. 1441009 ◽  
Author(s):  
Regina Ammer ◽  
Ulrich Rüde ◽  
Matthias Markl ◽  
Vera Jüchter ◽  
Carolin Körner
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Three Dimensional ◽  
Numerical Data ◽  
Process Window ◽  
Line Energy ◽  
Good Surface ◽  
Experimental Process ◽  
Numerical Process ◽  
Best Parameter

This paper validates three-dimensional (3D) simulation results of electron beam melting (EBM) processes by comparing experimental and numerical data. The physical setup is presented which is discretized by a 3D thermal lattice Boltzmann method (LBM). An experimental process window is used for the validation depending on the line energy injected into the metal powder bed and the scan velocity of the electron beam. In the process window, the EBM products are classified into the categories, porous, good and swelling, depending on the quality of the surface. The same parameter sets are used to generate a numerical process window. A comparison of numerical and experimental process windows shows a good agreement. This validates the EBM model and justifies simulations for future improvements of the EBM processes. In particular, numerical simulations can be used to explain future process window scenarios and find the best parameter set for a good surface quality and dense products.

Three-Dimensional TEM Tomography Analysis of Epitaxially Assembled Perovskite Oxide Nanocrystalline Particles

2008 ◽  
Vol 388 ◽  
pp. 127-130
Author(s):  
Naoki Iwaji ◽  
Hiromichi Takebe ◽  
Makoto Kuwabara
Keyword(s):  
Three Dimensional ◽  
Hydrothermal Condition ◽  
Perovskite Oxide ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Nanocrystalline Particles ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Tomography Analysis ◽  
Catio3 Nanoparticles

We investigated epitaxial assembly in aggregates of CaTiO3 nanoparticles, which were synthesized under a hydrothermal condition at 150°C using water/ethanol solvent, by transmission electron microscopy analysis combined with a three-dimensional tomography technique. The obtained results indicate that epitaxial assembly is involved in the crystal growth of CaTiO3 nanoparticles, and that in aggregates of CaTiO3 nanoparticles epitaxial assembly occur on their {101} planes.

scholarly journals Experimental and Numerical Investigations of a Novel Laser Impact Liquid Flexible Microforming Process

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 599 ◽  
Author(s):  
Fei Liu ◽  
Huixia Liu ◽  
Chenkun Jiang ◽  
Youjuan Ma ◽  
Xiao Wang
Keyword(s):  
Numerical Simulation ◽  
Laser Energy ◽  
Pure Copper ◽  
Three Dimensional ◽  
Element Model ◽  
Force Transmission ◽  
Large Area ◽  
Laser Impact ◽  
Metallic Foils

A novel high strain rate microforming technique, laser impact liquid flexible embossing (LILFE), which uses laser induced shock waves as an energy source, and liquid as a force transmission medium, is proposed by this paper in order to emboss three-dimensional large area micro arrays on metallic foils and to overcome some of the defects of laser direct shock microembossing technology. The influences of laser energy and workpiece thickness on the deformation characteristics of the pure copper foils with the LILFE process were investigated through experiments and numerical simulation. A finite element model was built to further understand the typical stages of deformation, and the results of the numerical simulation are consistent with those achieved from the experiments. The experimental and simulation results show that the forming accuracy and depth of the embossed parts increases with the increase in laser energy and decrease in workpiece thickness. The thickness thinning rate of the embossed parts increases with the decrease of the workpiece thickness, and the severest thickness thinning occurs at the bar corner region. The experimental results also show that the LILFE process can protect the workpiece surface from being ablated and damaged, and can ensure the surface quality of the formed parts. Besides, the numerical simulation studies reveal the plastic strain distribution of embossed microfeatures under different laser energy.

scholarly journals Electrical and rheological percolation behavior of multiwalled carbon nanotube-reinforced poly(phenylene sulfide) composites

2016 ◽  
Vol 51 (2) ◽  
pp. 199-208 ◽  
Author(s):  
B Ribeiro ◽  
RB Pipes ◽  
ML Costa ◽  
EC Botelho
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Three Dimensional ◽  
Polyphenylene Sulfide ◽  
Melt Mixing ◽  
Multiwalled Carbon ◽  
Single Screw Extruder ◽  
Percolation Behavior ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Polyphenylene sulfide-based nanocomposites filled with unmodified multiwalled carbon nanotubes from 0.5 wt% to 8.0 wt% have been prepared by melt mixing technique with a single-screw extruder and hot press. Transmission electronic microscopy and scanning electron microscopy analysis were carried out in order to assess the multiwalled carbon nanotubes dispersion throughout the polyphenylene sulfide matrix. Electrical conductivity of the polymer was dramatically enhanced by about 11 decades between 2.0 wt% and 3.0 wt% of nanotubes, suggesting the formation of three-dimensional conductive network within the polymeric matrix. The storage modulus (G′) of neat polyphenylene sulfide presented an increase by two orders of magnitude when 2.0 wt% of pristine multiwalled carbon nanotubes was considered, with the formation of an interconnected nanotube structure, indicative of “pseudo-solid-like” behavior. In addition, percolation networks were formed when the loading levels achieve up to 1.5 wt% for multiwalled carbon nanotubes/polyphenylene sulfide composites.

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