Characterization of Spatter and Sublimation in Alloy 718 during Electron Beam Melting

Abstract

Due to elevated temperatures and high vacuum levels in electron beam melting (EBM), spatter formation and accumulation in the feedstock powder, and sublimation of alloying elements from the base feedstock powder can affect the feedstock powder’s reusability and change the alloy composition of fabricated parts. This study focused on the experimental and thermodynamic analysis of spatter particles generated in EBM, and analyzed sublimating alloying elements from Alloy 718 during EBM. Heat shields obtained after processing Alloy 718 in an Arcam A2X plus machine were analyzed to evaluate the spatters and metal condensate. Comprehensive morphological, microstructural, and chemical analyses were performed using scanning electron microscopy (SEM), focused ion beam (FIB), and energy dispersive spectroscopy (EDS). The morphological analysis showed that the area coverage of heat shields by spatter increased from top (<1%) to bottom (>25%), indicating that the spatter particles had projectile trajectories. Similarly, the metal condensate had a higher thickness of ~50 μm toward the bottom of the heat shield, indicating more significant condensation of metal vapors at the bottom. Microstructural analysis of spatters highlighted that the surfaces of spatter particles sampled from the heat shields were also covered with condensate, and the thickness of the deposited condensate depended on the time of landing of spatter particles on the heat shield during the build. The chemical analysis showed that the spatter particles had 17-fold higher oxygen content than virgin powder used in the build. Analysis of the metalized layer indicated that it was formed by oxidized metal condensate and was significantly enriched with Cr due to its higher vapor pressure under EBM conditions.

Novel Cytochrome P450-3A4 Enzymatic Nanobiosensor for Lapatinib (a Breast Cancer Drug) Developed on a Poly(anilino-co-4-aminobenzoic Acid-Green-Synthesised Indium Nanoparticle) Platform

“…In the figure, we see that the only other elements present in the sample were carbon (C) and oxygen (O). However, the carbon element was from the carbon strip used for SEM analysis and the oxygen (O) element can be traced back to the reactor chamber’s residual oxygen [ 73 ]. This implies that the process of reducing the indium salt precursor’s oxide-reduction has been completed.…”

3D printing metal implants in orthopedic surgery: Methods, applications and future prospects

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Figure 1 The process of 3D printing metal implants (A) Personalized acquisition of patient imaging data, such as X-rays, CT, or MRI, (B) The orthopedic surgeon and engineer use CAD software to create a data model of the implant based on the patient's needs, which is converted into a series of 2D layer slices and saved as stereolithography (STL) data, (C Computer-controlled fabrication of the appropriate 3D printing technology melts the metal material layer by layer to print the molded model, and (D) Final finishing of the implant, such as grinding, coating, and surface oxidation techniques.

Figure 2 Metal additive manufacturing (A) selective laser sintering [ 13 ], (B) selective laser melting [ 14 ], (C) electron beam melting [ 15 ], (D) laser direct metal deposition [ 16 ], (E) laser induced forward transfer [ 17 ], (F) atomic diffusion additive manufacturing [ 18 ], reproduced with permission.

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“… Metal additive manufacturing (A) selective laser sintering [ 13 ], (B) selective laser melting [ 14 ], (C) electron beam melting [ 15 ], (D) laser direct metal deposition [ 16 ], (E) laser induced forward transfer [ 17 ], (F) atomic diffusion additive manufacturing [ 18 ], reproduced with permission. …”

“…Similar to SLS and SLM, electron beam melting (EBM) is a common 3D printing technique for metal implants that uses a high-energy, high-speed electron beam to bombard metal powders, melt the powdered material and form the product [ 20 , 15 ]. EBM is one of the most common 3D printing techniques applied for orthopedic metal implants, such as acetabular cups with outer porous mesh structure regions, femoral knee implants, and intramedullary rods [ 2 ].…”