The role of the inert gas during laser powder bed fusion (L-PBF) is to remove process by-products and air that initially present in chamber. On this purpose, different supply options are available. effect its purity, using argon nitrogen, on properties 316 L stainless steel produced by L-PBF was studied. results obtained showed utilization nitrogen result residual oxygen levels vary over course sequence It can be concluded a robust alloy L-PBF. A limited or type (argon nitrogen) tensile...

The generation of spatters during laser powder bed fusion (L-PBF) Alloy 718 is known to be detrimental for the re-use feedstock and quality final product. In this study, dedicated sampling from different positions within build chamber was performed. results clearly indicate importance surface-to-volume ratio built components on degradation, as demonstrated by analysis using capsules filled with dense lattice structures. Extensive formation Al- Cr-rich oxides entrained deposited gas inlet...

The influence of the process gas, laser scan speed, and sample thickness on build-up residual stresses porosity in Ti-6Al-4V produced by powder bed fusion was studied. Pure argon helium, as well a mixture those (30% helium), were employed to establish atmospheres with low oxygen content 100 ppm O2. results highlight that subsurface measured X-ray diffraction significantly lower thin samples (220 MPa) than cuboid (645 MPa). This difference attributed shorter vector length, resulting heat...

The effect of the residual oxygen concentration in process atmosphere during laser-powder bed fusion (L-PBF) Ti-6Al-4V was investigated, using an external monitoring system equipped with two types sensors typically used L-PBF hardware: a lambda probe and electrochemical sensor. recordings variations highlighted that sensor is more reliable than probe, whose signal showed maximum deviation about 700 ppm O2 after 7 h, attributed to its sensitivity hydrogen present system. study revealed proper...

Additive manufacturing provides a unique possibility to manufacture parts with advanced design and thin-walled structures. To explore thin-wall capacity, laser powder bed fusion was employed fabricate 316 ​L samples different section thicknesses. A detailed microstructure characterization then carried out, tensile properties were assessed. It found that reducing the part thickness did not affect but reduce properties. Samples 1 ​mm exhibited lowest yield strength of 457 ​± ​11 ​MPa...

In laser powder bed fusion (L-PBF), degradation is mainly driven by the accumulation of highly oxidized spatter particles in bed. Although amount spattering can be controlled melt pool stability, formation an unavoidable characteristic PBF processes. Oxidized risks defect printed components. However, factors influencing level oxidation during L-PBF processing are not yet fully understood. Herein, residual oxygen process atmosphere was reduced from traditionally applied 1000–20 ppm using...

Abstract The development of the laser powder bed fusion (L-PBF) process to increase its robustness and productivity is challenged by ambitious design optimizations, such as thin wall structures. In this study, in addition effect commonly used gases Ar N 2 , increased scanning speed new gases, helium, were successfully implemented. This implementation allowed build 316L stainless steel components with walls 1 mm thickness an enhanced rate 37 pct. sample size surface roughness held responsible...

Contour scanning and process gas type are parameters typically considered achieving second order effects compared to first factors such as laser power speed. The present work highlights that contour is crucial ensure geometrical accuracy thereby the high performance under uniaxial compression of complex Alloy 718 lattice structures. Studies X-ray computed tomography visualizations as-built compression-strained structures reveal continuous smooth bending walls, earlier onset internal contact...

High layer thicknesses for laser powder bed fusion are promising productivity increase. However, these associated with increased process instability, spatter generation and degradation, crucial alloys sensitive to oxygen. The effect of increasing thickness from 30 60 µm is studied focusing on Ti-6Al-4V formation during LPBF its characterisation, scanning transmission electron microscopy, combustion analysis X-ray photoelectron spectroscopy. Results indicate that spatters covered a uniform...

The detrimental effect of nitrogen and oxygen when it comes to the precipitation strengthening γ’’ γ’ phases in Alloy 718 is well-known from traditional manufacturing. Hence, influence two processing atmospheres, namely argon nitrogen, during laser powder bed fusion (L-PBF) parts was studied. Regardless gas type, considerable losses both about 150 ppm O2 (≈30%) on level around 400 N2 (≈25%) were measured comparison feedstock powder. utilization as atmosphere led a slightly higher content...

The dissolution of oxygen in Ti-6Al-4V during laser powder bed fusion (L-PBF) is a limitation for the final ductility produced components and challenge end-users. In present work, effect residual process atmosphere laboratory scale L-PBF machine, as well role heat accumulation, are studied. It was shown that content as-built determined by size scanned area build time. accumulation aspect investigated adjusting inter-layer time (ILT), increasing recoating or number parts. results showed...

The atmosphere is a vital factor influencing powder degradation during laser bed fusion. Particularly, its purity, density, and thermal conductivity, can strongly affect spatter generation, history, oxidation. It critical to understand the atmosphere-spatter properties relationship enhance recyclability overall process sustainability. Herein, effect of processing gases, among pure Ar, (Ar+He), He, on generation oxidation TiAl6V4 investigated. To evaluate their influence impurity pickup...

This study investigates the impact of powder layer thickness on spatter generation and oxidation behavior during processing Hastelloy X. In-situ monitoring using optical tomography reveals that thicker layers result in a higher number hot spatters generated laser-melt-powder interaction. Scanning electron microscopy Auger spectroscopy analysis demonstrate presence different types oxidize differently depending their origin. X-ray photoelectron further shows surface enrichment oxide-forming...

The utilisation of helium as process gas in laser powder bed fusion limits the generation Ti-6Al-4V hot and incandescent spatters enhances their cooling rate. In present study, operando X-ray diffraction using synchrotron X-rays permits to verify that rates experienced by deposited material are not significantly affected unlike spatters. Topography measurements top printed surface reveal lower roughness He-produced samples, attributed previously observed reduction with He thus a...

The novel Al-1Fe-1Zr alloy leverages the non-equilibrium solidification conditions characteristic of laser powder bed fusion (LPBF) process, namely a high thermal gradient (G) and front velocity (R). multiscale characterization its microstructure in as-built peak-aged by SEM, TEM with EDS automated crystal orientation mapping (ACOM), brings new insights on design for LPBF. permit solute trapping Fe Zr, latter precipitating as L12-Al3Zr nanoparticles following ageing, bringing strengthening...

Understanding the morphology, composition and structural changes experienced by metallic glass powder particles upon laser bed fusion (LPBF) is first step towards evaluating impact of spatter generation on part quality feedstock degradation. This study presents characterization Zr-Cu-Al-Nb means scanning transmission electron microscopy with automated crystallographic orientation mapping energy dispersive spectroscopy, X-ray photoelectron spectroscopy. The exposed to LPBF environment...

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