Some factors affecting porosity in directed energy deposition of AlMgScZr-alloys

Zhao, Tong; Wang, Yuhan; Xu, Tianshan; Bakir, Maha; Cai, Wangcan; Wang, Mengjie; Dahmen, Marius; Zheng, Qing; Wei, Xianke; Chen, Hong; Zhong, Chongliang; Albus, Patrick; Schopphoven, Thomas; Gasser, Andrés; Häfner, Constantin

doi:10.1016/j.optlastec.2021.107337

Cited by 24 publications

(4 citation statements)

References 31 publications

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“…The spindle axle is perpendicular or parallel to the nozzle axis, thus creating the single tracks or 3D-parts, respectively, as shown in Figure 4a-c. Since sufficient shielding gas flow is observed to improve the build quality of 3D-parts in DED [43], and considering that the nozzle's own shielding gas flow can be inadequate under open atmosphere when the travel speed is high, several shielding concepts were compared. For this, an additional shielding gas flow, a shielding sleeve, a smoke exhaust flue, an Al curtain, and a protective box were used, as shown in Figure 4d-i.…”

Section: Methodsmentioning

confidence: 99%

“…While enhancing the strengthening potential of individual tracks in this way, more harder track cores need to be preserved to improve the multi-layer performance overall. DED parts have been successfully built with scan speeds up to 40 m/min, but defects like high porosity still point to room for improvement [43]. By addressing these issues in the experiment, this work studies, in more detail, methods to improve the reachable hardness and strength of AlMgScZr alloys in DED, as shown in the approach in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

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Laser Directed Energy Deposition of an AlMgScZr-Alloy in High-Speed Process Regimes

et al. 2022

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Aluminum-magnesium-scandium-zirconium (AlMgScZr) alloys need to be rapidly cooled from the liquid state to obtain a high degree of solute supersaturation that helps to exploit the precipitation hardening potential of the material. While AlMgScZr alloys have been successfully used in laser powder bed fusion (LPBF) processes, there has been little research in the field of laser directed energy deposition (DED) of the material. The limited previous studies have shown that the performance of AlMgScZr parts fabricated with DED only reached about 60% of that of the parts fabricated with LPBF. In view of breaking through the limitation associated with the process conditions of conventional DED, this work demonstrates the DED of AlMgScZr alloys in high-speed process regimes and elucidates the mechanism of enhancing the hardness and tensile strength of AlMgScZr alloys by increasing the cooling rate by one to two orders of magnitudes, as well as reducing the track overlapping and the porosity of the specimens during the process. A maximum average hardness of nearly 150 HV0.1 and a max. tensile strength of 407 MPa are obtained by using an energy per unit length of 5400 J/m and a powder feed rate per unit length of 0.25 g/m.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laser Directed Energy Deposition of an AlMgScZr-Alloy in High-Speed Process Regimes

et al. 2022

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“…Svetlizky et al [39] have found that Al5083 powders acquired by gas atomization were transformed into Al5754 in composition due to the selective vaporization of elements during the LDED process. The powder mass flow rate and laser scan speed affected the evaporation degree of alloying elements to some extent [88,89]. The higher powder mass flow rate increases the flux of powder feed gas, which brings more oxygen to the melt pool from the air.…”

Section: 31mentioning

confidence: 99%

Review on laser directed energy deposited aluminum alloys

Liu,

Chen,

Qiu

et al. 2024

Int. J. Extrem. Manuf.

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The lightweight aluminum (Al) alloys have been widely used in frontier fields like aerospace and automotive industries, which attracts great interest in additive manufacturing to process high-value Al parts. As a mainstream additive manufacturing technique, laser directed energy deposition (LDED) shows good scalability to meet requirements for large-format components manufacturing and repairing. However, LDED Al alloys are highly challenging due to the inherent poor printability (e.g., low laser absorption, high oxidation sensitivity and cracking tendency). To further promote the development of LDED high-performance Al alloys, this review gains a deep understanding of the challenges and strategies to improve printability in LDED Al alloys. The porosity, cracking, distortion, inclusions, elements evaporation and resultant inferior mechanical properties (than laser powder bed fusion) are the key challenges in LDED Al alloys. Processing parameter optimizations, in-situ alloy design, reinforcing particle addition and field assistance are the efficient approaches to improve the printability and performance of LDED Al alloys. The underlying correlations between processes, alloy innovation, characteristic microstructures, and achievable performances in LDED Al alloys are discussed. The benchmarking mechanical properties and primary strengthening mechanism of LDED Al alloys are summarized. This review aims to provide a critical and in-depth evaluation of current progress in LDED Al alloys. The future opportunities and perspectives in LDED high-performance Al alloys are also outlooked.

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“…However, the rapid solidification characteristic of high-speed cladding limits the time available for gas to escape from the molten pool, promoting the formation of pores in the cladding layer. Gases may also be generated during the melting process due to impurities present in the powder [59,60] and on the substrate surface [61]. Gao et al [62] investigated the effect of the laser beam focus condition on the deposits.…”

Section: Porosity and Surface Appearancementioning

confidence: 99%

Microstructural characterization martensitic stainless-steel coatings deposited by laser metal deposition

Rodriguez,

Silva,

Torres

et al. 2024

Preprint

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Additive manufacturing (AM) technology, characterized by layer-by-layer deposition, is emerging as an alternative to produce parts, typically with complex geometries, and has recently become an option for mass production. This technology has been adopted by several industries due to its ability to save material resources and processing time. In addition, it could lead to component weight reduction, design optimization and the development of new materials. Among the AM processes, laser metal deposition (LMD) offers a high build rate and allows for larger deposition volumes compared to powder bed-based technology, resulting in lower manufacturing costs. Several industries, such as aerospace and defense, have focused on the use of LMD due to the opportunities for cost savings, increased productivity, and repair of large mechanical components. In particular, LMD could be used in the aerospace industry for the manufacture and repair of engines, turbines and propulsion systems, space shuttles, communications satellites. Currently, several types of metals, including important engineering materials such as steel, aluminum, and titanium, can be used to produce parts with high levels of precision and excellent properties. The use of martensitic stainless steels has increased in the automotive, aerospace and defense industries, mainly due to their mechanical properties such as high flow resistance and reasonable ductility. However, the deposition of martensitic stainless steels using LMD presents challenges in the selection of parameters, morphology configurations and phase evolutions to ensure the required mechanical properties. The objective of the present work was to evaluate the deposition parameters for laser cladding using LMD with martensitic stainless steel AISI 431 powder. In addition, morphological aspects were analyzed. The microstructural evolution was assessed using optical and electron microscopy. The results show dilution values between 10 and 27% were found for power values between 1400 and 1600 W and laser beam velocities of 9, 14 and 16 mm/s. Microstructural characterization revealed martensite and ferrite phases in the depositions. Several factors influence the geometric and microstructural characteristics of the laser cladded deposits, such as the morphology and size distribution of the filler particles, the chemical composition of the materials, the flow rate and deposition method of the filler, and the power and beam speed of the laser.

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Some factors affecting porosity in directed energy deposition of AlMgScZr-alloys

Cited by 24 publications

References 31 publications

Laser Directed Energy Deposition of an AlMgScZr-Alloy in High-Speed Process Regimes

Laser Directed Energy Deposition of an AlMgScZr-Alloy in High-Speed Process Regimes

Review on laser directed energy deposited aluminum alloys

Microstructural characterization martensitic stainless-steel coatings deposited by laser metal deposition

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