Investigation of laser metal deposited Alloy 718 onto an EN 1.4401 stainless steel substrate

Segerstark, Andreas; Andersson, Joel; Svensson, Lars-Erik

doi:10.1016/j.optlastec.2017.05.038

Cited by 22 publications

(16 citation statements)

References 21 publications

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“…Similar results were obtained by Chen et al [31], wherein the effect of P on H was not ascertained. A study by Segerstark et al [32] concluded that decrease in V and increase in Mp increased H, but P was found to have negligible effect on H. A study by Corbin et al [37] showed that H remained fairly constant over a certain P (250-400 W) and gradually increased with further increase in P when other process parameters remained unchanged, which ascertains the result obtained in the present study. Change in Lo did not show any significant effect on H as seen in Figure 4a.…”

Section: Effect Of Laser Power and Laser Stand-off Distance On The Gesupporting

confidence: 87%

“…The G value gradually decreased towards the top region of the deposit where equiaxed grain morphology was noticed [38,40]. The dendritic growth at the top edge of the deposit indicated a secondary growth front that nucleated from partially melted powders and also due to shielding gas interaction with the melt-pool, that provided a suitable condition for heterogeneous nucleation away from the solidification front [32]. The heat dissipation by partially melted powder particles is minimal as compared to the substrate, and the cooling rates achieved in this region are low compared to the bottom of the deposit.…”

Section: Grain Morphologymentioning

confidence: 99%

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Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718

Sreekanth

Ghassemali

Hurtig

et al. 2020

Metals

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The effect of three important process parameters, namely laser power, scanning speed and laser stand-off distance on the deposit geometry, microstructure and segregation characteristics in direct energy deposited alloy 718 specimens has been studied. Laser power and laser stand-off distance were found to notably affect the width and depth of the deposit, while the scanning speed influenced the deposit height. An increase in specific energy conditions (between 0.5 J/mm2 and 1.0 J/mm2) increased the total area of deposit yielding varied grain morphologies and precipitation behaviors which were comprehensively analyzed. A deposit comprising three distinct zones, namely the top, middle and bottom regions, categorized based on the distinct microstructural features formed on account of variation in local solidification conditions. Nb-rich eutectics preferentially segregated in the top region of the deposit (5.4–9.6% area fraction, Af) which predominantly consisted of an equiaxed grain structure, as compared to the middle (1.5–5.7% Af) and the bottom regions (2.6–4.5% Af), where columnar dendritic morphology was observed. High scan speed was more effective in reducing the area fraction of Nb-rich phases in the top and middle regions of the deposit. The <100> crystallographic direction was observed to be the preferred growth direction of columnar grains while equiaxed grains had a random orientation.

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Section: Effect Of Laser Power and Laser Stand-off Distance On The Gesupporting

confidence: 87%

Section: Grain Morphologymentioning

confidence: 99%

Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718

Sreekanth

Ghassemali

Hurtig

et al. 2020

Metals

Self Cite

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show abstract

“…A custom configuration of such working principle was previously demonstrated on a wire-LMD setup for the process control [26]. Subsequent works reported the usage of commercial laser displacement sensors [27][28][29][30] or 3D scanners [31]. In general, these kinds of high-precision instruments are characterized by a nominal resolution of few micrometers, allowing very accurate measurements during the process.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of laser metal deposition height by means of coaxial laser triangulation

Donadello

Motta

Demir

et al. 2019

Optics and Lasers in Engineering

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“…Micrographs of the morphology and cross sections of the powder have previously been reported. [5] The chemical composition of the powder and substrate are shown in Table I. A 6-kW ytterbium fiber laser that produced an Ø 1.6 mm laser spot on the deposition surface was used as energy source.…”

Section: Methods and Experimentsmentioning

confidence: 99%

“…The parameter settings were adapted from previous reported studies [6][7][8][9] and initial experiments. [5] HI ¼…”

Section: Methods and Experimentsmentioning

confidence: 99%

Effect of Process Parameters on the Crack Formation in Laser Metal Powder Deposition of Alloy 718

Segerstark

Andersson

Svensson

et al. 2018

Metall Mater Trans A

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Cracking in Alloy 718 using laser metal powder deposition has been evaluated in this study. It is found that the material is susceptible to cracking when the laser power is high, the scanning speed is high, and the powder-feeding rate is low. Almost all the cracks are located close to the center of the deposited wall and propagate in the normal direction to the substrate. Evidence of liquation are found at the cracked surfaces, and since all cracks reside in regions which are reheated several times, the cracks are determined to most likely be heat-affected zone liquation cracks. The influence of respective process parameter was evaluated using a design of experiment approach. It is shown that, when the powder-feeding rate is incorporated as a variable, the heat input is not a suitable indicator for the hot cracking susceptibility in laser metal powder deposition of Alloy 718. A combinatory model using the power density together with the heat input is therefore proposed.

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Investigation of laser metal deposited Alloy 718 onto an EN 1.4401 stainless steel substrate

Cited by 22 publications

References 21 publications

Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718

Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718

Monitoring of laser metal deposition height by means of coaxial laser triangulation

Effect of Process Parameters on the Crack Formation in Laser Metal Powder Deposition of Alloy 718

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