Melt Pool Boundaries Research Articles

Vision-based in-situ monitoring system for melt-pool detection in laser powder bed fusion process

A low-cost, lateral off-axis non-IR imaging system is proposed to inspect the melt-pool in the Laser Powder Bed Fusion (L-PBF) processing of IN718 powder and stainless steel 316 L powder. In the proposed system, a perspective transformation method is applied to transform the captured side-view image into a top-view image and the melt-pool boundary is then determined based on an inspection of the gray-level intensity profile of the captured image and its first derivative. For the IN718 L-PBF process, the measurement results obtained for the melt-pool width and melt-pool length vary by no more than 13% and 3%, respectively, from the experimental results reported in the literature. For the SS316L, the measured melt-pool width is within 6% of the ex-situ measurements obtained by optical microscopy, while the melt-pool length differs by no more than 9% from the numerical predictions. Overall, the results show that the proposed system provides a viable means of detecting potential build failures during the L-PBF process and improving the yield of the fabrication process as a result.

A critical look at the prediction of the temperature field around a laser-induced melt pool on metallic substrates

The study of microstructure evolution in additive manufacturing of metals would be aided by knowing the thermal history. Since temperature measurements beneath the surface are difficult, estimates are obtained from computational thermo-mechanical models calibrated against traces left in the sample revealed after etching, such as the trace of the melt pool boundary. Here we examine the question of how reliable thermal histories computed from a model that reproduces the melt pool trace are. To this end, we perform experiments in which one of two different laser beams moves with constant velocity and power over a substrate of 17-4PH SS or Ti-6Al-4V, with low enough power to avoid generating a keyhole. We find that thermal histories appear to be reliably computed provided that (a) the power density distribution of the laser beam over the substrate is well characterized, and (b) convective heat transport effects are accounted for. Poor control of the laser beam leads to potentially multiple three-dimensional melt pool shapes compatible with the melt pool trace, and therefore to multiple potential thermal histories. Ignoring convective effects leads to results that are inconsistent with experiments, even for the mild melt pools here.

Marine Atmospheric Corrosion of Additively Manufactured Stainless Steels

Additively manufactured (AM) stainless steels (SSs) exhibit numerous microstructural differences compared to their wrought counterparts, such as Cr-enriched dislocation cell structures. The influence these unique features have on a SSs corrosion resistance are still under investigation with most current works limited to laboratory experiments. The work herein shows the first documented study of AM 304L and 316L exposed to a severe marine environment on the eastern coast of Florida with comparisons made to wrought counterparts. Coupons were exposed for 21 months and resulted in significant pitting corrosion to initiate after 1 month of exposure for all conditions. At all times, the AM coupons exhibited lower average and maximum pit depths than their wrought counterparts. After 21 months, pits on average were 4 μm deep for AM 316L specimen and 8 μm deep for wrought specimen. Pits on the wrought samples tended to be nearly hemispherical and polished with some pits showing crystallographic attack while pits on AM coupons exhibited preferential attack at melt pool boundaries and the cellular microstructure.

Microstructure and magnetic properties of Nd-Fe-B permanent magnets produced by laser powder bed fusion

Additive manufacturing of Nd-Fe-B is a novel approach for the fabrication of permanent magnets. We present an analysis of the magnetic properties and microstructure of Nd-Fe-B permanent magnets, which were produced by laser powder bed fusion (LPBF). By optimization of processing parameters for the Nd-lean powder coercivity of 921 kA/m (1.16 T), remanence of 0.63 T and maximum energy product of 63 kJ/m3 are achieved without the addition of further Nd-rich low-melting alloys or any other post treatment. Thereby, remanence and maximum energy product represent the highest reported values for additively manufactured permanent magnets. The impact of area energy density EA on the magnetic properties is discussed. The isotropic microstructure consists of short Nd2Fe14B dendrites at the melt pool boundaries and globular sub-micron sized grains in the melt pool interior. After LPBF of the Nd-lean powder no evidence of α-Fe is found in the microstructure.

Microstructure and constitutive model for flow behavior of AlSi10Mg by Selective Laser Melting

This work is devoted to investigate the flow behavior and microstructure evolution of AlSi10Mg by additive manufacturing in hot deformation. Tensile test is carried out under different temperatures, i.e. 200 ∘ C, 250 ∘ C, 300 ∘ C, 350 ∘ C and 400 ∘ C, with various strain rates of 0.004/s, 0.002/s and 0.0004/s. Theoretically, the modified Arrhenius-type model of additive manufacturing materials at high temperature is established. Experimentally, scanning electron microscope and optical microscope are used to analyze the mechanism of hot deformation. It is found that at 200 ∘ C both the dendritic eutectic Si and acicular eutectic Si precipitate, forming cellular structure and strengthening phases. And then, the acicular eutectic Si is partially dissolved into Al matrix, but there is no obvious growth of dendritic Si at 300 ∘ C. With the temperature increasing, the cellular structure and melt pool boundary gradually disappear. For 400 ∘ C temperature, like homogenization process, the precipitation of saturated solid solution forms the dispersed phase, and the stress-strain curve shows a weak hardening. Meanwhile, the statistical result shows that that the constitutive model agrees well with the experimental results at high temperature. This study may provide guidance for the improvement of additive manufacturing material properties by post-treatment. • The modified Arrhenius-type equation of AlSi10Mg is theoretically established. • Microscope images show that the micropores may decrease as the temperature rises. • The melt pool, heat affected zone and remelt zone are weakened under hot deformation. • The precipitates are spheroidized under hot deformation at 400 ∘ C. • Evolution of AlSi10Mg: saturation precipitate and dispersion strengthened stage.

Additive Manufacturing of High Strength Copper Alloy With Heterogeneous Grain Structure Through Laser Powder Bed Fusion

The low laser processability of pure copper (Cu) commonly causes high porosity, and therefore low strength of additively manufactured (AMed) Cu parts. The current work reports an effective approach to solve this problem through inoculation of pure Cu powder with cobalt (Co) submicron particles. Co addition enabled increase in laser absorptivity, and therefore dense Cu was fabricated through laser powder bed fusion even though typical AM featured coarse columnar grains were produced when Co addition was 4 wt.% or less. Significant grain refinement with heterogeneous grain structure (HGS) was achieved when the addition level was greater than the maximum solid solubility of Co in Cu (4.75 wt.%), such as 6 and 8 wt.%. HGS is characterized with ultrafine equiaxed grains close to melt pool boundaries and coarser equiaxed grains or columnar grains near centres of melt pools. Heterogenous nucleation of Cu near melt pool boundaries, where were associated with larger thermal undercooling due to faster cooling rate, was responsible for the formation of ultrafine equiaxed grains. In contrast, heterogeneous nucleation near centres of melt pools was suppressed. Detailed substructure examination indicated that heterogenous nucleation occurred on dual phase nanoparticles containing Co shell and cobalt oxide (CoO) core. The higher affinity of Co to oxygen caused formation of CoO. HGS of Cu significantly improved both strength and ductility. After direct ageing at 600°C for one hour, a tensile strength of 491.1±12.6 MPa, elongation of 27.3±2.5% and electrical conductivity of 61.5% IACS (International Annealed Copper Standard) were achieved.

An investigation into melting modes in selective laser melting of Inconel 625 powder: single track geometry and porosity

The laser process parameters used in selective laser melting (SLM) affect the mode of melting and the process characteristics such as the porosity. Some parameters may have a higher effect on the single-track characteristics than the others. This study aims at determining both the individual and combined effects of laser parameters on the single-track geometry and porosity for Inconel 625 alloy powder. The single tracks with linear energy densities (LED) ranging from 0.16 to 0.98 J/mm are fabricated to explore the effect of LED on melting modes and the keyhole porosity. A micro-CT scanner is used to measure the pores formed inside the tracks, and the results showed that the porosity increased with an increase in LED in the keyhole mode. Besides, metallography is performed to reveal the transverse melt pool boundary and to differentiate the melting modes. The transverse melt pool boundary shows that the depth of the melt pool increases significantly compared to the width with an increase in LED, which signifies the change in the melting from the conduction to keyhole mode. Further, another set of experiments is performed by using different combinations of laser power and scan speed from the same LEDs of 0.48 J/mm and 0.75 J/mm. The melt pool boundary shows that within the same LED, the depth of the melt pool increases significantly with an increase in the laser power. However, for the same LED, the single-track porosity increased up to a certain level; then, the porosity decreased with the further increase in the power and speed. The physics behind such phenomenon is explained by the particle-level SLM process simulations developed using FLOW-3D. The simulation results show that the change in the melting mode from the conduction to keyhole for the same LED is due to the increased vaporization with an increase in the laser power, which enhanced the vapor pressure.

An accurate and real-time melt pool dimension measurement method for laser direct metal deposition

Laser direct metal deposition (LDMD), as a type of additive manufacturing (AM) technology, has gained broad applications across many industries. However, producing high-quality and accurate geometric workpieces remains a challenge without controlling the fabrication process. A visual-based process monitoring system provides information about melt pool dimensions as vital process parameters for controlling the LDMD process. As the result, the accuracy of the measurement determines the performance of the control system. This paper proposes a method that includes an efficient approach for obtaining the melt pool dimensions in real time and a novel melt pool boundary calibration for finding a suitable threshold to achieve high measurement accuracy. The proposed method is verified on an LDMD system, and the experimental results show that the proposed approach has provided accurate measurements of the melt pool widths that can be used for process quality control.

Fracture resistance of AlSi10Mg fabricated by laser powder bed fusion

The combination of refined microstructures (induced by rapid cooling) and melt pool-induced mesostructures in AlSi10Mg fabricated using laser powder bed fusion (LPBF) – a widely used additive manufacturing technique – impart high strength and fracture toughness. Further exploitation of such property combinations requires a detailed understanding of how the processing conditions control the micro- and mesostructures and, in turn, the mechanical performance, especially regarding fracture resistance. Towards this end, the crack resistance curve (R-curve) behavior in different orientations of LPBF-fabricated AlSi10Mg alloys processed with different layer thickness, hatch spacing, and scan strategies was evaluated and correlated with micro- and mesostructural features such as grain size and grain orientation, texture, cell morphology, and melt pool arrangement. Results show a strong anisotropy in both tensile stress-strain behavior and fracture toughness with layer thickness and hatch spacing controlling strength and scan strategy dictating fracture resistance. In terms of tensile stress-strain behavior, the arrangement of melt pool boundaries with respect to loading direction results in anisotropy in ductility whereas strength is controlled by grain size and cellular structure. In case of fracture toughness, measurements show that failure is dominated primarily by melt pool morphology and hence the mesostructure that is controlled by scan strategy. They furthermore reveal, that, despite the pronounced anisotropy in the R-curve behavior the presence of such mesostructure enables a level of damage-tolerance in AlSi10Mg that cannot be achieved in a cast alloy.

Effect of Hydrogen on the Tensile Behavior of Austenitic Stainless Steels 316L Produced by Laser-Powder Bed Fusion

Hydrogen was doped in austenitic stainless steel (ASS) 316L tensile samples produced by the laser-powder bed fusion (L-PBF) technique. For this aim, an electrochemical method was conducted under a high current density of 100 mA/cm2 for three days to examine its sustainability under extreme hydrogen environments at ambient temperatures. The chemical composition of the starting powders contained a high amount of Ni, approximately 12.9 wt.%, as a strong austenite stabilizer. The tensile tests disclosed that hydrogen charging caused a minor reduction in the elongation to failure (approximately 3.5% on average) and ultimate tensile strength (UTS; approximately 2.1% on average) of the samples, using a low strain rate of 1.2 × 10−4 s−1. It was also found that an increase in the strain rate from 1.2 × 10−4 s−1 to 4.8 × 10−4 s−1 led to a reduction of approximately 3.6% on average for the elongation to failure and 1.7% on average for UTS in the pre-charged samples. No trace of martensite was detected in the X-ray diffraction (XRD) analysis of the fractured samples thanks to the high Ni content, which caused a minor reduction in UTS × uniform elongation (UE) (GPa%) after the H charging. Considerable surface tearing was observed for the pre-charged sample after the tensile deformation. Additionally, some cracks were observed to be independent of the melt pool boundaries, indicating that such boundaries cannot necessarily act as a suitable area for the crack propagation.

An investigation of the anisotropic properties of heat-treated maraging steel grade 300 processed by laser powder bed fusion

In order to explore the possibilities enabled by laser beam powder bed fusion of metals (PBF-LB/M), reliable material models are necessary to optimize designs with respect to weight and stiffness. Due to the unique processing conditions in PBF-LB/M, materials often develop a dominating microstructure that leads to anisotropic mechanical properties, and thus isotropic material models fail to account for the orientation-dependent mechanical properties. To investigate the anisotropy of 18Ni300 maraging steel, tensile specimens were built in seven different orientations. The specimens were heat treated at two different conditions and tested for their tensile properties using digital image correlation (DIC) technique. The microstructure and fracture surfaces are investigated with scanning electron microscope and electron backscatter diffraction. The tensile properties are typical for the material, with a yield strength in the range of 1850 MPa to 1950 MPa, and ultimate tensile strength in the range of 1900 MPa to 2000 MPa. The elastic modulus is 180 GPa, and the elongation at fracture is in the range of 2–6% for all specimens. The strain fields analysed with DIC reveals anisotropic straining in both the elastic and plastic parts of the flow curve for both direct ageing and solution treatment plus ageing specimens. In the former condition, the elastic anisotropy is dictated by the fraction of melt pool boundaries on the transverse surfaces of the specimens. When the material is solution treated prior to ageing, the melt pool boundary effect was supressed.

Tensile Mechanical Behavior and Spall Response of a Selective Laser Melted 17-4 PH Stainless Steel

The tensile mechanical behavior and spall response of a selective laser melted (SLM) 17-4 precipitation-hardening (PH) stainless steel were studied comprehensively through tensile test, plate impact experiment and microstructure characterization in the present study. The results reveal a steel with significant strain rate dependence on the tensile mechanical behavior and spall response. As the strain rate increases, the tensile yield stress increases, but there is no monotonic variation trend for the peak stress; grain structure remains unchanged first and then becomes fine; high-angle grain boundaries (HAGBs) increase; the martensite phase decreases at first and then increases. There is a close correlation among impact velocity, strain rate, peak stress, Hugoniot elastic limit (HEL) and spall strength. Strain rate, peak stress and HEL increase, while spall strength remains almost constant with the increase of impact velocity. As impact velocity increases, grain structure becomes fine, HAGBs increase and the martensite phase increases. The significant phase transformation is responsible for the tensile mechanical behavior and spall response, and the temperature rise was calculated to analyze its effect on phase transformation. Whether the preferred orientations are along the building direction or tensile direction is dependent on strain rate. Tensile and spallation specimens exhibit the ductile fracture mode and the damage originates from voids. It is interesting that the voids always tend to nucleate at melt pool boundaries. A spall damage evolution model is illustrated to describe the damage process.

Processability and Optimization of Laser Parameters for Densification of Hypereutectic Al–Fe Binary Alloy Manufactured by Laser Powder Bed Fusion

Centimeter-sized samples of hypereutectic Al–15 mass% Fe alloy were manufactured by a laser powder bed fusion (L-PBF) process while systematically varying laser power (P) and scan speed (v). The effects on relative density and melt pool depth of L-PBF-manufactured samples were investigated. In comparison with other Al alloys, a small laser process window of P = 77–128 W and v = 0.4–0.8 ms−1 was found for manufacturing macroscopically crack-free samples. A higher v and P led to the creation of macroscopic cracks propagating parallel to the powder-bed plane. These cracks preferentially propagated along the melt pool boundaries decorated with brittle θ-Al13Fe4 phase, resulting in low L-PBF processability of Al–15%Fe alloy. The deposited energy density model (using P·v−1/2) would be useful for identifying the optimum L-PBF process conditions towards densification of Al–15%Fe alloy samples, in comparison with the volumetric energy density (using P·v−1), however, the validity of the model was reduced for this alloy in comparison with other alloys with high thermal conductivities. This is likely due to inhomogeneous microstructures having numerous coarsened θ–Al13Fe4 phases localized at melt pool boundaries. These results provide insights into achieving sufficient L-PBF processability for manufacturing dense Al–Fe binary alloy samples.

Studies on Tensile Behaviour of Selective Laser Melted 316L Stainless Steel Using SEM Straining Stage

Metallic components prepared by additive manufacturing are expected to exhibit microstructural anisotropy due to their layer-by-layer architecture. This in-homogeneity in microstructure can result in variations in the deformation behaviour of materials in different directions, which may lead to premature failure of a component loaded in a particular orientation. Therefore, in the present study, an attempt has been made to investigate the microstructural characteristics and ensuing mechanical properties, in three different orientations with respect to the build direction in a 316L stainless steel, printed using selective laser melting technique. Tensile tests were performed on micro-tensile specimens using a straining stage attached to scanning electron microscope (SEM) while observing crack initiation and propagation. The results were compared with that of conventionally processed AISI 316L stainless steel. Microstructural analysis of the SLM printed component revealed the presence of fine cellular structure within the clearly defined prior melt-pool boundaries. Furthermore, EBSD analysis revealed the presence of columnar grains, which were mostly oriented along the to direction in the build plane and along the direction in the long transverse plane. The favourable grain orientation for twinning in the samples drawn along the build plane led to a better accommodation of plastic strain during tensile deformation. Hence, the sample drawn from build plane showed an improved combination of strength and ductility, in comparison to the transverse orientations. When compared with conventionally processed 316L stainless steel, the SLM printed samples showed a significant increase in the strength in all the three orientations with a concurrent decrease in the ductility.

Experimental and numerical investigation of the origin of surface roughness in laser powder bed fused overhang regions

ABSTRACT Surface roughness of laser powder bed fusion (L-PBF) printed overhang regions is a major contributor to deteriorated shape accuracy/surface quality. This study investigates the mechanisms behind the evolution of surface roughness (Ra) in overhang regions. The evolution of surface morphology is the result of a combination of border track contour, powder adhesion, warp deformation, and dross formation, which is strongly related to the overhang angle (θ). When 0° ≤ θ ≤ 15°, the overhang angle does not affect Ra significantly since only a small area of the melt pool boundaries contacts the powder bed resulting in slight powder adhesion. When 15° < θ ≤ 50°, powder adhesion is enhanced by the melt pool sinking and the increased contact area between the melt pool boundary and powder bed. When θ > 50°, large waviness of the overhang contour, adhesion of powder clusters, severe warp deformation and dross formation increase Ra sharply.

The dependence of hydrogen embrittlement on hydrogen transport in selective laser melted 304L stainless steel

The mechanical property and hydrogen transport characteristics of selective laser melting (SLM) 304L stainless steel were investigated by tensile tests and thermal desorption spectroscopy (TDS). The heat treatment affected the hydrogen embrittlement (HE) susceptibility and the treatment at 950 °C showed the larger HE effects. Cellular structures and melt-pool boundaries were dissolved at 850 and 950 °C, respectively. TDS results indicate that the hydrogen diffusivity of the as-received SLM 304L was lower than that of wrought 304L and the hydrogen diffusion activation energy increased with the recrystallisation degree, which was related to the dislocation density. Dislocations, rather than strain-induced martensite, were the main cause of HE owing to the high austenite stability of the samples. The pre-existing dislocations in the SLM 304L sample heat-treated at 950 °C for 4 h affected the hydrogen transport behaviour during sample stretching and led to severe HE.

A virtual sensing approach for monitoring melt-pool dimensions using high speed coaxial imaging during laser powder bed fusion of metals

Abstract Metal parts produced by Laser Powder Bed Fusion (L-PBF) are frequently used for demanding applications. To meet stringent safety and certification requirements, a better understanding of melt-pool behavior and stability during processing is desired. This work presents a novel, fast and economically feasible virtual sensing approach for accurate estimation of melt-pool depth and width during L-PBF of metals. In a first step, the melt-pool width is determined by GPU-based processing of images from a high-speed coaxial camera monitoring system. In a second step, a physics-based analytical model is used to calculate the melt-pool depth-to-width ratio from the processing conditions and material properties. In a third and last step, the results from the first two steps are combined to estimate the melt-pool depth. Experimental validation of these predicted melt-pool dimensions is performed on 316L SS single layer strips that are consecutively produced, cross-sectioned, polished and etched to reveal the actual melt-pool boundaries. The results indicate an average relative error on the predicted melt-pool depth of 9.9% and 2.8% for the full L-PBF parameter range and for the optimal parameter range respectively. This gives confidence in the predictive capabilities of a virtual sensing approach using coaxial camera images for the assessment of the melt-pool depth and process stability.

Microstructural evolution and martensitic transformation in FeCrV alloy fabricated via additive manufacturing

FeCrV alloy (high-wear-resistance steel or HWS) has been extensively used in additive manufacturing for hardfacing and repairing owing to its excellent hardness, superior weldability, and wear resistance. This alloy must possess superior mechanical property under harsh environments, such as friction and wear, to facilitate its application in repairing gears and strengthening the surface of a die locally. HWS deposited by directed energy deposition was subjected to heat treatment by quenching and tempering (QT) to improve the mechanical property and investigate the influence of martensitic transformation. During the solidification of the molten pool, the as-deposited HWS exhibited compressive residual stress (−102 (±72) MPa) on the surface, resulting from martensitic transformation. In contrast, the surface of the heat-treated HWS (HT-HWS) had tensile residual stress (150 (±34) MPa), which was induced by released carbon from the matrix and decarburization at the surface. QT heat treatment precipitated spherical chromium carbide (W0·07Mo0·07Cr1·31V0·31Fe1·38C) and rod-like vanadium carbide (W0·07Mo0·08Cr0·48V0·56Fe1·08C) on the grain boundaries and nanosized-vanadium carbide on the martensite lath boundaries. During heat treatment, the austenite of the as-deposited HWS transformed into martensite, and only 4.80% of the austenite remained. Despite heat treatment, the dislocation density did not decrease because the martensitic transformation caused plastic deformation of the adjacent grains. In addition, the precipitation of fine carbide inhibited grain growth during the heat treatment. For these reasons, the hardness of the as-deposited HWS increased by 17% (i.e., from 659 (±18.7) HV to 773 (±3.33) HV), corresponding to the hardness of carburized SCM420 (774 (±4.31) HV). The tensile strength of the as-deposited HWS increased from 570.6 (±21.5) MPa to 848.1 (±47.7) MPa by removing the melt pool boundary and needle-shaped austenite which are the crack propagation paths of the QT-heat-treated alloy. The carbide that precipitated during heat treatment changed the fracture mechanism from intergranular with dimples to cleavage.

Correlative Synchrotron X-ray Imaging and Diffraction of Directed Energy Deposition Additive Manufacturing

The governing mechanistic behaviour of Directed Energy Deposition Additive Manufacturing (DED-AM) is revealed by a combined in situ and operando synchrotron X-ray imaging and diffraction study of a nickel-base superalloy, IN718. Using a unique DED-AM process replicator, real-space imaging enables quantification of the melt-pool boundary and flow dynamics during solidification. This imaging knowledge was also used to inform precise diffraction measurements of temporally resolved microstructural phases during transformation and stress development with a spatial resolution of 100 µm. The diffraction quantified thermal gradient enabled a dendritic solidification microstructure to be predicted and coupled to the stress state. The fast cooling rate entirely suppressed the formation of secondary phases or recrystallisation in the solid-state. Upon solidification, the stresses rapidly increase to the yield strength during cooling. This insight, combined with the large solidification range of IN718 suggests that the accumulated plasticity exhausts the ductility of the alloy, causing liquation cracking. This study has revealed the mechanisms that govern the formation of highly non-equilibrium microstructures during DED-AM.

Effect of input powder attributes on optimized processing and as-built tensile properties in laser powder bed fusion of AlSi10Mg alloy

A systematic material characterization approach is presented to demonstrate the critical impact of input powder attributes on the optimized parameters and the as-built properties in the Laser Powder Bed Fusion (LPBF) of AlSi10Mg alloy. Two batches of powders (conventional and specialty) with widely different attributes, including particles’ morphology, size distribution, internal oxidation, surface chemistry and roughness, were separately investigated for the optimized LPBF parameters. It is showed that the specialty powder with a spherical morphology and a larger mean particle size exhibits a higher flowability, as well as a higher apparent density. The latter, together with a smoother surface topography in the specialty powder particles (thus a lower laser absorptivity), necessitates a higher volumetric energy density (VED) requirement for a complete fusion during the LPBF. The as-built microstructures which resulted from both powders show a similar evolution of total porosity content, melt-pool boundaries and solidification structure, both qualitatively and quantitatively, which is consistent with their comparable YS values. The specialty powder, however, yields a higher UTS and %El in the as-built state, which is believed to be due to a scarce presence of O-rich particles (which otherwise preside primarily within the intercellular regions, as is the case for the conventional powder). The emergence of such O-rich particles in the as-built microstructure could be traced back to the powder source (i.e., in the form of internal O-rich phases and a thick oxide surface layer in the conventional powder). In other words, an O-lean powder translates into an O-lean printed part. One-time recycling of the specialty powder is shown to have a negligible effect on its morphological characteristics, and thus on the optimized set of parameters, consistently yielding as-built YS values similar to those of the original powder. The as-built UTS and %El values resulting from the recycled powder, however, are notably lower than those from the original powder, which are suggested to be due to the presence of contaminants and/or oxide inclusions resulting from the LPBF processing itself and/or during the recycling procedure (e.g., sieving). We believe the correlations established here between the input powder attributes and the LPBF performance of AlSi10Mg alloy can be applicable to many metallic systems.