A thermal finite element model with efficient computation of surface heat fluxes for directed-energy deposition process and application to laser metal deposition of IN718

Dörtkaşlı, Kerem; Isik, Murat; Demir, Eralp

doi:10.1016/j.jmapro.2022.04.049

Cited by 19 publications

(8 citation statements)

References 64 publications

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“…To estimate the uniformity of temperature distribution of molten pool, the temperature non-uniformity

is calculated. The formula of temperature non-uniformity is as follows [ 10 ]:

where, i deontes the i th cell and V i represents the cell volume. T ave is the average temperature of the molten pool and is calculated using volume averaging method.…”

Section: Resultsmentioning

confidence: 99%

“…A substantial amount of numerical model has been proposed based on reasonable simplifications because of the complex physical phenomena involved in the L-DED process. Dortkasli et al [ 10 ] developed an efficient finite element model for thermal process to predict the characteristics of the clad layer in the L-DED process. However, the fluid flow of the liquid metal was not taken into account in the simulation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Laser Beam Profile on Thermal Transfer, Fluid Flow and Solidification Parameters during Laser-Based Directed Energy Deposition of Inconel 718

Chen

Bian

et al. 2023

Materials

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The profile of the laser beam plays a significant role in determining the heat input on the deposition surface, further affecting the molten pool dynamics during laser-based directed energy deposition. The evolution of molten pool under two types of laser beam, super-Gaussian beam (SGB) and Gaussian beam (GB), was simulated using a three-dimensional numerical model. Two basic physical processes, the laser–powder interaction and the molten pool dynamics, were considered in the model. The deposition surface of the molten pool was calculated using the Arbitrary Lagrangian Eulerian moving mesh approach. Several dimensionless numbers were used to explain the underlying physical phenomena under different laser beams. Moreover, the solidification parameters were calculated using the thermal history at the solidification front. It is found that the peak temperature and liquid velocity in the molten pool under the SGB case were lower compared with those for the GB case. Dimensionless numbers analysis indicated that the fluid flow played a more pronounced role in heat transfer compared to conduction, especially in the GB case. The cooling rate was higher for the SGB case, indicating that the grain size could be finer compared with that for the GB case. Finally, the reliability of the numerical simulation was verified by comparing the computed and experimental clad geometry. The work provides a theoretical basis for understanding the thermal behavior and solidification characteristics under different laser input profile during directed energy deposition.

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“…To estimate the uniformity of temperature distribution of molten pool, the temperature non-uniformity

is calculated. The formula of temperature non-uniformity is as follows [ 10 ]:

where, i deontes the i th cell and V i represents the cell volume. T ave is the average temperature of the molten pool and is calculated using volume averaging method.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Laser Beam Profile on Thermal Transfer, Fluid Flow and Solidification Parameters during Laser-Based Directed Energy Deposition of Inconel 718

Chen

Bian

et al. 2023

Materials

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“…Their model can fairly predict the transition in the melt pool with varying input parameters. Many numerical studies have been conducted on DED processes with commonly used alloys such as Ti-6Al-4V [24,27] , Inconel 718 [28][29][30] , and so on. For highly sophisticated applications in aviation, more material models should be performed.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation on melt pool and solidification in the direct energy deposition process of GH3536 powder superalloy

Liu

Liu²,

Li³

et al. 2023

Preprint

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In the direct energy deposition (DED) process, the highly energetic laser, rapid melting, and solidification processes lead to complex heat transfer and flow phenomena. A three-dimensional finite element model (FEM) is established to study the effect of process parameters on the melt pool and solidification quality during the DED process. The heat transfer, fluid flow, and solidification in the DED process of the GH3536 superalloy are studied. By investigating the effects of laser power, scanning speed, and feed rate on the morphology of melt pool and interlayer fusion, the appropriate input parameters for GH3536 are obtained. Temperature gradient and solidification rate obtained in transient thermal distribution are applied to predict the quality and morphology of the solidified structure at the cut-off point. Results show that high laser power and low scanning speed or feed rate will enlarge the melt pool. Well-solidified microstructure frequently appears in the middle of the parameter set; focusing on the enlargement of the melt pool is not the best strategy. The correlation between feed rate and laser power is not obvious. The minimum threshold for scanning speed is found at a given feed rate. When the scanning rate is below the threshold, abnormal morphology of the melt pool and irregular solidification structures will occur. The laser power and scanning speed range suitable for the GH3536 superalloy are summarized, and the undesirable and possibly fluctuating parameters are marked. The middle part of the parameter set is recommended for the feed rate.

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“…Additive manufacturing (AM) has recently gained enormous attention, particularly from the aerospace industry since AM possesses many advantages over conventional manufacturing processes (Gokhale and Kala, 2022; Mehrpouya et al , 2022; Ren et al , 2022). The majority of metal AM researches are focused on selective laser melting, electron beam melting and direct energy deposition (Facchini et al , 2009; Bandyopadhyay et al , 2019; Avila et al , 2020; Isik et al , 2020; Balkan et al , 2021; Dortkasli et al , 2022). AM improves the manufacturing cycle time of complex parts in a cost-effective manner since AM eliminates the need for excessive machining and the utilization of expensive tooling (Parandoush et al , 2021; Bagherzadeh et al , 2022).…”

Section: Introductionmentioning

confidence: 99%

The effect of additively and subtractively created center internal features on microstructure and mechanical performance of inconel-718 parts

Isik,

Emami Tabrizi,

Khan

et al. 2023

RPJ

Self Cite

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Purpose In recent years, additive manufacturing (AM) has started to be used for manufacturing real functional parts and assemblies for critical applications in aerospace, automotive, and machinery industries. Most complex or assembled parts require internal features (IF) such as holes, channels, slots, or guides for locational and mating requirements. Therefore, it is critical to understand and compare the structural and mechanical properties of additively manufactured and conventionally machined IFs. Design/methodology/approach In this study, mechanical and microstructural properties of Inconel 718 (Inc718) alloy internal features, manufactured either as-built with AM or machining of additively manufactured (AMed) part thereafter were investigated. Findings The results showed that the average ultimate tensile strength (UTS) of additively manufactured center internal feature (AM-IF) is almost analogous to the machined internal feature (M-IF). However, the yield strength of M-IF is greater than that of AM-IF due the greater surface roughness of the internal feature in AM-IF, which is deemed to surpass the effect of microstructure on the mechanical performance. The results of digital image correlation (DIC) analysis suggest that AM-IF and M-IF conditions have similar strain values under the same stress levels but the specimens with as built IF have a more locally ductile region around their IF, which is confirmed by hardness test results. But this does not change global elongation behavior. The microstructural evolution starting from as-built (AB) and heat-treated (HT) samples to specimens with IF are examined. The microstructure of HT specimens has bimodal grain structure with d phase while the AB specimens display a very fine dendritic microstructure with the presence of carbides. Although they both have close values, machined specimens have a higher frequency of finer grains based on SEM images. Originality/value It was shown that the concurrent creation of the IF during AM can provide a final part with a preserved ultimate tensile strength and elongation but a decreased yield strength. The variation in UTS of AM-IF increases due to the surface roughness near the internal feature as compared to smooth internal surfaces in M-IF. Hence, the outcomes of this study are believed to be valuable for the industry in terms of determining the appropriate production strategy of parts with IF using AM and postprocessing processes.

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A thermal finite element model with efficient computation of surface heat fluxes for directed-energy deposition process and application to laser metal deposition of IN718

Cited by 19 publications

References 64 publications

Effect of Laser Beam Profile on Thermal Transfer, Fluid Flow and Solidification Parameters during Laser-Based Directed Energy Deposition of Inconel 718

Effect of Laser Beam Profile on Thermal Transfer, Fluid Flow and Solidification Parameters during Laser-Based Directed Energy Deposition of Inconel 718

Numerical simulation on melt pool and solidification in the direct energy deposition process of GH3536 powder superalloy

The effect of additively and subtractively created center internal features on microstructure and mechanical performance of inconel-718 parts

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