Effect of beam current on the microstructure, crystallographic texture and mechanical properties of electron beam welded high purity niobium

2021 ◽  
pp. 111318
Author(s):  
Kalyan Das ◽  
Abhishek Ghosh ◽  
Avisor Bhattacharya ◽  
Harishchandra Lanjewar ◽  
Jyotsna Dutta Majumdar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
High Purity ◽  
Crystallographic Texture ◽  
Beam Current

Correlation Between Microstructure and Mechanical Properties in an Inconel 718 Deposit Produced Via Electron Beam Freeform Fabrication

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Wesley A. Tayon ◽  
Ravi N. Shenoy ◽  
MacKenzie R. Redding ◽  
R. Keith Bird ◽  
Robert A. Hafley
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Crystallographic Texture ◽  
Inconel 718 ◽  
Electron Backscatter Diffraction ◽  
Microstructural Characterization ◽  
Freeform Fabrication ◽  
Aerospace Applications ◽  
Evolution Of Microstructure ◽  
Texture Characterization

Electron beam freeform fabrication (EBF3), a metallic layer-additive manufacturing process, uses a high-power electron beam in conjunction with a metal feed wire to create a molten pool on a substrate, which on solidification produces a component of the desired configuration made of sequentially deposited layers. During the build-up of each solidified layer, the substrate is translated with respect to the electron beam and the feed wire. EBF3 products are similar to conventional cast products with regard to the as-deposited (AD) microstructure and typical mechanical properties. Inconel 718 (IN 718), a high-temperature superalloy with attractive mechanical and oxidation properties well suited for aerospace applications, is typically used in the wrought form. The present study examines the evolution of microstructure, crystallographic texture, and mechanical properties of a block of IN 718 fabricated via the EBF3 process. Specimens extracted out of this block, both in the AD and in a subsequently heat treated (HT) condition, were subjected to (1) microstructural characterization using scanning electron microscopy (SEM); (2) in-plane elastic modulus, tensile strength, and microhardness evaluations; and (3) crystallographic texture characterization using electron backscatter diffraction (EBSD). Salient conclusions stemming from this study are: (1) mechanical properties of the EBF3-processed IN 718 block are strongly affected by texture as evidenced by their dependence on orientation relative to the EBF3 fabrication direction, with the AD EBF3 properties generally being significantly reduced compared to wrought IN 718; (2) significant improvement in both strength and modulus of the EBF3 product to levels nearly equal to those for wrought IN 718 may be achieved through heat treatment.

Microstructure and Mechanical Properties of Electron Beam Deposits of AISI 316L Stainless Steel

2011 ◽  
Author(s):  
Liang Wang ◽  
Sergio D. Felicelli ◽  
Jacob Coleman ◽  
Rene Johnson ◽  
Karen M. B. Taminger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Electron Beam ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Beam Current ◽  
Aisi 316L ◽  
Translation Speed ◽  
Aisi 316L Stainless Steel ◽  
Microstructure And Mechanical Properties

Electron beam freeform fabrication (EBF3) is a process that uses an electron beam and wire feedstock to fabricate metallic parts inside a vacuum chamber. In this study, single and multiple layer linear deposits of AISI 316L stainless steel were produced with the EBF3 machine at NASA Langley Research Center (LaRC). EBF3 process parameters, including beam current, translation speed, and wire feed rate, were investigated in order to consider their effects on the resulting steel deposit geometry, microstructure and mechanical properties. Results indicate that the EBF3 process can produce pore-free, fully dense material within the range of process parameters used in this study. The electron beam deposited stainless steel has a solidification microstructure with fine columnar grains within most parts of the deposit due to the high cooling rate during the deposition, with some small homogeneous equiaxed grains at the top of the deposit. The mechanical properties of the deposits are comparable to those of wrought metal, which is attributed to the homogeneous fine-grained microstructure.

TEM -analysis of the BeO-dispersion in high purity Be-ingots

1978 ◽  
Vol 36 (1) ◽  
pp. 636-637
Author(s):  
Hans Migge
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Oxide Scale ◽  
High Purity ◽  
Ultrahigh Vacuum ◽  
Particle Sizes ◽  
Tem Analysis ◽  
Tremendous Importance ◽  
Thin Oxide ◽  
To Come

Inclusions of BeO are of tremendous importance on the mechanical properties of Beryllium [1,2]. The BeO particle sizes of different hot pressed materials are in the range between 400 Å and 10 μm for BeO contents between 0.5 and 3.6%[3]. However, there is no investigation about the BeO dispersion in high purity (<200 ppm BeO) ingots. Information on this subject should be derived from the diffuse Debye rings of BeO, which as yet are thought to come from the very thin oxide scale on the Be-surface [3].0.1 mm foils of Berylco IF—1 from KBI with BeO < 200 ppm were analyzed at 100 kV in the as received condition or after annealing for 1 hour at 900°C in ultrahigh vacuum. With the electron beam parallel to [00.1], [11.1], [02.1], [12.1], [03.1], [12.2] (using different grains) always four diffuse BeO rings of the type {10.0}, {10.1}, {11.0}and the unresolved {20.0}/{11.2} appear in the SAD-pattern.

scholarly journals Effect of Strain Rate on the Tensile Mechanical Properties of Electron Beam Welded OFE Copper and High-Purity Niobium for SRF Applications

2021 ◽  
Author(s):  
J.-F. Croteau ◽  
M. Peroni ◽  
S. Atieh ◽  
N. Jacques ◽  
E. Cantergiani
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Yield Stress ◽  
High Purity ◽  
High Speed ◽  
Strain Rates ◽  
High Speed Forming ◽  
Elongation To Failure ◽  
Ofe Copper ◽  
Srf Cavities

AbstractAn investigation of the tensile mechanical properties of electron beam welded OFE copper and high-purity niobium sheets is presented. Specimens were deformed in tension at strain rates ranging from 10−3 to ~ 1600 s−1. The 0.2% yield stress and ultimate tensile strength (UTS) of the welded niobium specimens are similar to those of unwelded specimens at strain rates lower or equal to 20 s−1. At higher strain rates, these mechanical properties are lower for welded niobium specimens. The 0.2% yield stress of welded OFE copper specimens is consistently lower than unwelded specimens over the range of strain rates studied, while the UTS is comparable at all strain rates. The elongation to failure of welded OFE copper specimens remains unchanged at all strain rates while the ductility of niobium specimens reduces at strain rates greater or equal to 20 s−1 and reaches a minimum at ~ 400 s−1. The effects of the weld on a non-standardized short specimen geometry, developed for this study to obtain strain rates in the order of 103 s−1, are more pronounced for niobium due to large grain sizes (up to 1200 μm) in the fusion region. However, comparable strength and ductility trends, with respect to a standard specimen, were measured at low strain rates. The conservation of strength and the relatively high ductility of the welded sheets, especially for OFE copper, suggest that bent and electron beam welded tubes could be used for the fabrication of seamless superconducting radiofrequency (SRF) cavities. These results are promising for the use of high-speed forming techniques, like electro-hydraulic forming, for the manufacturing of parts using welded tubes and sheets.

Effect of Energy Density of Incident Beam on Mechanical Property of Titanium Alloy Products Fabricated by Electron Beam Melting (EBM) Method

2012 ◽  
Vol 706-709 ◽  
pp. 488-491 ◽  
Author(s):  
Hidetsugu Fukuda ◽  
Hiroyuki Takahashi ◽  
Koichi Kuramoto ◽  
Takayoshi Nakano
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Energy Density ◽  
Deformation Behavior ◽  
Electron Beam Melting ◽  
Testing Machine ◽  
Incident Beam ◽  
Beam Current ◽  
Electron Beam Current ◽  
Layer By Layer

Electron beam melting (EBM) is a promising fabrication technique for directly producing metal products from powder as the starting material. Powders are provided as a thin layer (~100 μm) and melted layer by layer with an electron beam. In this study, the effects of the energy density of the incident beam on the mechanical properties of Ti–6 mass% Al–4 mass% V alloy products fabricated through EBM were examined. The products were fabricated using an electron beam at various energy densities depending on the electron beam current. The microstructures and crystallographic orientations were observed using optical microscopy and electron backscatter diffraction (EBSD), respectively. Compression tests were carried out in 2 loading directions using a mechanical testing machine equipped with strain gauges, one perpendicular (x–y direction) and the other parallel (z direction) to the stacking direction. In principle, the microstructure consisted of an acicular-shaped α phase (hcp lattice) and a small-volume β phase (bcc lattice). In addition, columnar grains elongated toward the z direction appeared during the repeated melting and solidification that occurred during the EBM process. An increase in the beam current of the incident beam enlarged the α grains and increased the relative density, resulting in the related Young’s modulus of the products. The energy density caused by the beam current also introduces anisotropy in the deformation behavior depending on the loading axis toward the stacking direction. This is closely related to the cast defect arranged along the stacking layers. It was concluded that the mechanical properties of the Ti–6 mass% Al–4 mass% V alloy products formed through EBM were very sensitive to the incident beam current and stacking direction, resulting in the exhibition of anisotropic deformation behavior within a limited range of energy density.

Sign in / Sign up

Export Citation Format

Share Document