Temperature Profile, Bead Geometry, and Elemental Evaporation in Laser Powder Bed Fusion Additive Manufacturing Process

Ahsan, Faiyaz; Ladani, Leila

doi:10.1007/s11837-019-03872-3

Cited by 38 publications

(16 citation statements)

References 28 publications

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“…Figure 10 presents a representative comparison, for example, when the laser power employed was 200 W. Both width and depth increased as the scan speed decreased, but the calculated values are always lower than the experimental results, especially at low scan speed, i.e., higher volumetric energy density and for melt pool depth. Therefore, to fully utilize the simplicity of Rosenthal solutions, temperature dependent thermo-physical properties, energy density dependent absorption, and depth due to keyholing [44], among others should be investigated in detail to better model the temperature distribution and melt pool development [61][62][63]. Figure 11 presents engineering stress vs. engineering strain responses of three tensile specimens built with an optimized set of parameters: 200 W laser power, 800 mm/s scan speed, 0.12 mm hatch spacing and 0.03 mm slice thickness, corresponding to a volumetric energy density of ~69 J/mm 3 .…”

Section: Melt Pool Dimension Estimated By Rosenthal Solutionmentioning

confidence: 99%

Process Optimization and Microstructure Analysis to Understand Laser Powder Bed Fusion of 316L Stainless Steel

Vallejo

Lucas

Ayers

et al. 2021

Metals

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The microstructural development of 316L stainless steel (SS) was investigated over a wide range of systematically varied laser powder bed fusion (LPBF) parameters, such as laser power, scan speed, hatch spacing and volumetric energy density. Relative density, melt pool width and depth, and the size of sub-grain cellular structure were quantified and related to the temperature field estimated by Rosenthal solution. Use of volumetric energy density between 46 and 127 J/mm3 produced nearly fully dense (≥99.8%) samples, and this included the best parameter set: power = 200 W; scan speed = 800 mm/s; hatch spacing = 0.12 mm; slice thickness = 0.03; energy density = 69 J/mm3). Cooling rate of 105 to 107 K/s was estimated base on the size of cellular structure within melt pools. Using the optimized LPBF parameters, the as-built 316L SS had, on average, yield strength of 563 MPa, Young’s modulus of 179 GPa, tensile strength of 710 MPa, and 48% strain at failure.

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Section: Melt Pool Dimension Estimated By Rosenthal Solutionmentioning

confidence: 99%

Process Optimization and Microstructure Analysis to Understand Laser Powder Bed Fusion of 316L Stainless Steel

Vallejo

Lucas

Ayers

et al. 2021

Metals

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“…The ABAQUS 6.20 SOFTWARE (2020, Johnston, RI, USA) is used to carry out the numerical simulation for understanding the effect of interlayer delay on the temperature distribution of the WAAM process. In order to model layer deposition, the “element birth technique” is utilized [ 21 ]. In this technique, material properties are progressively switched from quiet to active values according to the deposition process as it requires specific elements activation techniques [ 21 ] in simulating material deposition.…”

Section: Numerical Modelmentioning

confidence: 99%

“…In order to model layer deposition, the “element birth technique” is utilized [ 21 ]. In this technique, material properties are progressively switched from quiet to active values according to the deposition process as it requires specific elements activation techniques [ 21 ] in simulating material deposition. The basic principle is that quiet material has an extremely low thermal conductivity, hence filler elements in quiet state will experience a significant increase in temperature only if they are directly heated by the external power source.…”

Section: Numerical Modelmentioning

confidence: 99%

“…The basic principle is that quiet material has an extremely low thermal conductivity, hence filler elements in quiet state will experience a significant increase in temperature only if they are directly heated by the external power source. In this work, activation start and end temperature are set according to material liquidus and solidus temperatures, respectively [ 21 ].…”

Section: Numerical Modelmentioning

confidence: 99%

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Effect of Interlayer Delay on the Microstructure and Mechanical Properties of Wire Arc Additive Manufactured Wall Structures

et al. 2021

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Wire arc additive manufacturing is a metal additive manufacturing technique that allows the fabrication of large size components at a high deposition rate. During wire arc additive manufacturing, multi-layer deposition results in heat accumulation, which raises the preheat temperature of the previously built layer. This causes process instabilities, resulting in deviations from the desired dimensions and variations in material properties. In the present study, a systematic investigation is carried out by varying the interlayer delay from 20 to 80 s during wire arc additive manufacturing deposition of the wall structure. The effect of the interlayer delay on the density, geometry, microstructure and mechanical properties is investigated. An improvement in density, reduction in wall width and wall height and grain refinement are observed with an increase in the interlayer delay. The grain refinement results in an improvement in the micro-hardness and compression strength of the wall structure. In order to understand the effect of interlayer delay on the temperature distribution, numerical simulation is carried out and it is observed that the preheat temperature reduced with an increase in interlayer delay resulting in variation in geometry, microstructure and mechanical properties. The study paves the direction for tailoring the properties of wire arc additive manufacturing-built wall structures by controlling the interlayer delay period.

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“…The L-PBF process can generate temperatures up to 10 5 • C and cooling rates between 10 6 -10 8 • C/s within the melt pool [4]. It is difficult to measure the temperature profile in the melt pool, however modelling has been used to measure the thermal response within the process [5]. These processing conditions can lead to aggressive melt pool instabilities leading to the formation of spatter particles [6], ejected powder, metal vapours and condensate plumes as by-products of the focussed heating process.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

Harkin

Nikam

et al. 2021

Metals

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The Laser-based Powder Bed Fusion (L-PBF) process uses a laser beam to selectively melt powder particles deposited in a layer-wise fashion to manufacture components derived from Computer-Aided Design (CAD) information. During laser processing, material is ejected from the melt pool and is known as spatter. Spatter particles can have undesirable geometries for the L-PBF process, thereby compromising the quality of the powder for further reuse. An integral step in any powder replenishing and reuse procedure is the sieving process. The sieving process captures spatter particles within the exposed powder that have a diameter larger than a defined mesh size. This manuscript reports on Ti6Al4V (Grade 23) alloy powder that had been subjected to seven reuse iterations, focusing on the characterisation of powder particles that had been captured (i.e., removed) by the sieving processes. Characterisation included chemical composition focusing upon interstitial elements O, N and H (wt.%), particle morphology and particle size analysis. On review of the compositional analysis, the oxygen contents were 0.43 wt.% and 0.40 wt.% within the 63 µm and 50 µm sieve-captured powder, respectively. Additionally, it was found that a minimum of 79% and 63% of spatter particles were present within the captured powder removed by the 63 µm and 50 µm sieves, respectively.

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Temperature Profile, Bead Geometry, and Elemental Evaporation in Laser Powder Bed Fusion Additive Manufacturing Process

Cited by 38 publications

References 28 publications

Process Optimization and Microstructure Analysis to Understand Laser Powder Bed Fusion of 316L Stainless Steel

Process Optimization and Microstructure Analysis to Understand Laser Powder Bed Fusion of 316L Stainless Steel

Effect of Interlayer Delay on the Microstructure and Mechanical Properties of Wire Arc Additive Manufactured Wall Structures

Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

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