Powder reuse and its contribution to porosity in additive manufacturing of Ti6Al4V

Ghods, S.; Schur, R.; Schultz, E.; Pahuja, Rishi; Montelione, A.; Wisdom, C.; Arola, D.

doi:10.1016/j.mtla.2020.100992

Cited by 29 publications

(7 citation statements)

References 44 publications

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“…Microtomography (microCT), which is commonly used to study the porosity of AM parts in relation to their mechanical properties 24 , 25 , can also be used to study the influence of powder reuse on pore and particle size distribution. While some researchers have used microCT to study the porosity of reused powder 7 , 26 , Ghods et al 27 recently investigated the porosity of printed Ti6Al4V AM parts using microCT and found that over 30 printing cycles powder reuse had no significant impact on the total porosity, pore size distribution or sphericity of pores.…”

Section: Introductionmentioning

confidence: 99%

“…The novelty of this paper is a special focus on three-time-used powder for the fabrication of dental objects and a holistic approach to the study of microstructural and corrosion properties and its effect on the porosity and hardness properties, which are important for applications in dentistry. Namely, the results from the published literature are related to multiple recycling cycles 13 , 15 , 16 , 27 , whereas the corrosion resistance of 3D printed objects made from new and recycled powders has not been yet compared. We focused on examining the properties of powder particles after a few cycles of reuse, as well as on the porosity and microstructural, mechanical and corrosion properties of a 3D printed structure intended for dental use.…”

Section: Introductionmentioning

confidence: 99%

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The microstructure, mechanical and electrochemical properties of 3D printed alloys with reusing powders

Leban

Hren

Kosec

2023

Sci Rep

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CoCrMo and Ti6Al4V are widely used in medical, dental and 3D printing technology, allowing the accurate fabrication of geometrically complicated structures. In order to reduce the costs of printed objects, the reuse of powder is common daily practice. When using 3D printing technology, the direct impact of elevated temperatures and the influence of the laser beam may change the properties of the powder when it is reused, thus affecting the final properties of the printed object. The main aim of the present study was to investigate the impact of reused powder on the mechanical, microstructural and electrochemical properties of 3D printed objects. 3D printed objects fabricated from virgin and reused powder of both alloys were analyzed by metallographic observation, computed tomography, XRD and electrochemical methods. The main finding of the study was that the use of reused powder (recycled 3 times) does not detrimentally affect the mechanical and corrosion integrity of 3D printed CoCr and Ti6Al4V alloys, especially for the purpose of applications in dentistry.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The microstructure, mechanical and electrochemical properties of 3D printed alloys with reusing powders

Leban

Hren

Kosec

2023

Sci Rep

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“…Similarly, Ghods and coworkers [11] showed an increase in oxygen content from 0.14% in virgin powder to 0.20% in reused after 11 cycles. A follow-up study showed the effect of powder reuse on porosity formation during the processing of TiAl6V4, where no distinguishable change in porosity in fabricated parts was observed even after 30 cycles of powder reuse [16]. However, the effect of oxygen enrichment in Ti alloys on mechanical properties is well known where an increase in oxygen content increases the hardness and decreases the room temperature ductility [17,18].…”

Section: Introductionmentioning

confidence: 99%

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

Raza¹,

Hryha²

2021

Materials

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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.

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“…High strength and low thermal conductivity are the causes of difficulties with the machinability of Ti-6Al-4V [ 3 , 4 ], and it is important to find ways to increase machinability by cutting titanium alloys. Although the development of additive manufacturing provides a new way for the process of titanium alloy parts [ 5 , 6 , 7 ], the cutting-based subtractive manufacturing is still the main processing method for high-precision parts such as integral bladed disks, casings, and key components of aircraft [ 8 , 9 ]. Ball-end cutters are the commonly used tools in the milling process of Ti-6Al-4V, which have strong adaptability to the change of surface curvature [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Study on the Formation Mechanism of Surface Adhered Damage in Ball-End Milling Ti6Al4V

et al. 2021

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Ball-end cutters are widely used for machining the parts of Ti-6Al-4V, which have the problem of poor machined surface quality due to the low cutting speed near the tool tip. In this paper, through the experiments of inclined surface machining in different feed directions, it is found that the surface adhered damages will form on the machined surface under certain tool postures. It is determined that the formation of surface adhered damage is related to the material adhesion near the cutting edge and the cutting-into/out position within the tool per-rotation cycle. In order to analyze the cutting-into/out process more clearly under different tool postures, the projection models of the cutting edge and the cutter workpiece engagement on the contact plane are established; thus, the complex geometry problem of space is transformed into that of plane. Combined with the case of cutting-into/out, chip morphology, and surface morphology, the formation mechanism of surface adhered damage is analyzed. The analysis results show that the adhered damage can increase the height parameters Sku, Sz, Sp, and Sv of surface topographies. Sz, Sp, and Sv of the normal machined surface without damage (Sku ≈ 3) are about 4–6, 2–3, and 2–3 μm, while Sz, Sp, and Sv with adhered damage (Sku > 3) can reach about 8–20, 4–14, and 3–6 μm in down-milling and 10–25, 7–18, and 3–7 μm in up-milling. The feed direction should be selected along the upper left (Q2: β∈[0°, 90°]) or lower left (Q3: β∈[90°, 180°]) to avoid surface adhered damage in the down-milling process. For up-milling, the feed direction should be selected along the upper right (Q1: β∈(−90°, 0°]) or upper left (Q2: β∈[0°, 90°)).

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Powder reuse and its contribution to porosity in additive manufacturing of Ti6Al4V

Cited by 29 publications

References 44 publications

The microstructure, mechanical and electrochemical properties of 3D printed alloys with reusing powders

The microstructure, mechanical and electrochemical properties of 3D printed alloys with reusing powders

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

Study on the Formation Mechanism of Surface Adhered Damage in Ball-End Milling Ti6Al4V

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