scholarly journals Nanostructuring of Nb-Si-Cr Alloys by Electron Beam Melting to Improve the Mechanical Properties and the Oxidation Behavior

2021 ◽  
Author(s):  
A. Förner ◽  
J. Vollhüter ◽  
D. Hausmann ◽  
C. Arnold ◽  
P. Felfer ◽  
...  
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Electron Beam Melting ◽  
Room Temperature ◽  
Single Layer ◽  
Atom Probe ◽  
Cooling Rates ◽  
High Cooling Rates ◽  
Very High

AbstractMaterials processed by additive manufacturing often exhibit a very fine-scaled microstructures due to high cooling rates in the process. In this study, single-layer surface electron beam melting is used to create very high cooling rates similar to additive manufacturing processes to investigate the resulting microstructure. In the case of Nb-Si-Cr in-situ composites, a nano-scaled eutectic microstructure is beneficial for improving the mechanical and oxidational properties. Fast solidification results in the formation of supersaturated phases of Nbss and Cr2Nb with phase diameters down to 10 nm as well as in the stabilization of the metastable Nb9(Cr,Si)5 phase at room temperature. After processing with different solidification rates, the decomposition of the Nb9(Cr,Si)5 phase has been studied in detail with atom probe microscopy. The stabilization of mixed silicide phases by electron beam melting shows a new pathway for improving hardness and enhancing oxidation resistance of nanostructured eutectic in-situ composites, by which the inherent weaknesses of Nb-Si-Cr can be overcome without further alloying elements. Graphical Abstract

scholarly journals Nanoscaled eutectic NiAl-(Cr,Mo) composites with exceptional mechanical properties processed by electron beam melting

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Andreas Förner ◽  
S. Giese ◽  
C. Arnold ◽  
P. Felfer ◽  
C. Körner ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Electron Beam Melting ◽  
Lamellar Microstructure ◽  
High Hardness ◽  
Additive Process ◽  
In Situ Composites ◽  
Selective Electron Beam Melting ◽  
Very High

Abstract Eutectic NiAl-(Cr,Mo) composites are promising high temperature materials due to their high melting point, excellent oxidation behavior and low density. To enhance the strength, hardness and fracture toughness, high cooling rates are beneficial to obtain a fine cellular-lamellar microstructure. This can be provided by the additive process of selective electron beam melting. The very high temperature gradient achieved in this process leads to the formation of the finest microstructure that has ever been reported for NiAl-(Cr,Mo) in-situ composites. A very high hardness and fracture toughening mechanisms were observed. This represents a feasibility study towards additive manufacturing of eutectic NiAl-(Cr,Mo) in-situ composites by selective electron beam melting.

scholarly journals Feasibility of in situ controlled heat treatment (ISHT) of Inconel 718 during electron beam melting additive manufacturing

2017 ◽  
Vol 13 ◽  
pp. 156-165 ◽  
Author(s):  
W.J. Sames ◽  
K.A. Unocic ◽  
G.W. Helmreich ◽  
M.M. Kirka ◽  
F. Medina ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Inconel 718 ◽  
Electron Beam Melting

scholarly journals Contactless temperature measurement in wire-based electron beam additive manufacturing Ti-6Al-4V

2021 ◽  
Author(s):  
F. Pixner ◽  
R. Buzolin ◽  
S. Schönfelder ◽  
D. Theuermann ◽  
F. Warchomicka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Thermal Imaging ◽  
Temperature Profiles ◽  
Layer By Layer ◽  
Thermal Cycles ◽  
Cooling Rates ◽  
Geometric Boundary ◽  
Microstructural Characterisation ◽  
Local Misorientation

AbstractThe complex thermal cycles and temperature distributions observed in additive manufacturing (AM) are of particular interest as these define the microstructure and the associated properties of the part being built. Due to the intrinsic, layer-by-layer material stacking performed, contact methods to measure temperature are not suitable, and contactless methods need to be considered. Contactless infrared irradiation techniques were applied by carrying out thermal imaging and point measurement methods using pyrometers to determine the spatial and temporal temperature distribution in wire-based electron beam AM. Due to the vacuum, additional challenges such as element evaporation must be overcome and additional shielding measures were taken to avoid interference with the contactless techniques. The emissivities were calibrated by thermocouple readings and geometric boundary conditions. Thermal cycles and temperature profiles were recorded during deposition; the temperature gradients are described and the associated temperature transients are derived. In the temperature range of the α+β field, the cooling rates fall within the range of 180 to 350 °C/s, and the microstructural characterisation indicates an associated expected transformation of β→α'+α with corresponding cooling rates. Fine acicular α and α’ formed and local misorientation was observed within α as a result of the temperature gradient and the formation of the α’.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

Realizing a full volume component by in-situ welding during electron beam melting process

2018 ◽  
Vol 22 ◽  
pp. 375-380 ◽  
Author(s):  
Pan Wang ◽  
Mui Ling Sharon Nai ◽  
Wai Jack Sin ◽  
Shenglu Lu ◽  
Baicheng Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Melting Process ◽  
Electron Beam Melting Process ◽  
Full Volume
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