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Thermal Operating Window in Selective Laser Melting Processes Cover

Thermal Operating Window in Selective Laser Melting Processes

Transactions on Aerospace Research
Volume 2023 (2023): Issue 4 (December 2023)
By: Jerzy Kozak,  Tomasz Zakrzewski,  Marta Witt and  Martyna Dębowska-Wąsak  
Open Access
|Dec 2023

Figures & Tables

Figure 1.

Additive manufactured GE9X engine components: (A) T25 sensor housing; (B) fuel nozzle tip; and (C) low-pressure turbine blades (adopted from reference [1]).
Additive manufactured GE9X engine components: (A) T25 sensor housing; (B) fuel nozzle tip; and (C) low-pressure turbine blades (adopted from reference [1]).

Figure 2.

Scheme of the fabrication stages: A – data preparation, B – manufacturing stage, C – the physical part (figures adopted from reference [2]).
Scheme of the fabrication stages: A – data preparation, B – manufacturing stage, C – the physical part (figures adopted from reference [2]).

Figure 3.

Schematic diagram of laser sintering melting (SLM) showing the key phenomena occurring during the process.
Schematic diagram of laser sintering melting (SLM) showing the key phenomena occurring during the process.

Figure 4.

The diagram of phases changes during energy input into powder. Point A with melting temperature Tm represents the lower thermal limit, and point B has temperature TB = Tb – ΔTB where TB is the upper thermal limit.
The diagram of phases changes during energy input into powder. Point A with melting temperature Tm represents the lower thermal limit, and point B has temperature TB = Tb – ΔTB where TB is the upper thermal limit.

Figure 5.

The scheme of the single-track melting and multitrack structures.
The scheme of the single-track melting and multitrack structures.

Figure 6.

The cross-sections of the tracks (A) simulation vs experimental sample. Track width at different laser travel speeds of (B) 1,050 mm/s, (C) 1,250 mm/s and (D) 1,450 mm/s (material: Ti-6Al; laser power: 175 W) (adopted from reference [8]).
The cross-sections of the tracks (A) simulation vs experimental sample. Track width at different laser travel speeds of (B) 1,050 mm/s, (C) 1,250 mm/s and (D) 1,450 mm/s (material: Ti-6Al; laser power: 175 W) (adopted from reference [8]).

Figure 7.

Schematic approximation of the cross-section by parabolic profile (A) and elliptical profile (B).
Schematic approximation of the cross-section by parabolic profile (A) and elliptical profile (B).

Figure 8.

Scheme of heating of the powder layer. Model dimensions: a, h, l.
Scheme of heating of the powder layer. Model dimensions: a, h, l.

Figure 9.

Thermal conductivity coefficient ke for the powder material for the solid and liquid phases.
Thermal conductivity coefficient ke for the powder material for the solid and liquid phases.

Figure 10.

The model of the bed layer and the used mesh (A); simulation of heating and melting of powder with a laser beam (B).
The model of the bed layer and the used mesh (A); simulation of heating and melting of powder with a laser beam (B).

Figure 11.

Plot of temperature distribution during heating P = 70 W, V = 1,200 mm/s. (cross-section perpendicular to the laser path; refer to Fig. 10).
Plot of temperature distribution during heating P = 70 W, V = 1,200 mm/s. (cross-section perpendicular to the laser path; refer to Fig. 10).

Figure 12.

Plot of the operating window and results of simulation and experiments.
Plot of the operating window and results of simulation and experiments.

Figure 13.

Simulation result of SLM at the following laser powers: (A) below lower thermal limit; (B) between lower and upper thermal limits; (C and D) exceeding the upper thermal limit. SLM, selective laser melting.
Simulation result of SLM at the following laser powers: (A) below lower thermal limit; (B) between lower and upper thermal limits; (C and D) exceeding the upper thermal limit. SLM, selective laser melting.

Figure 14.

The result of the SLM when the process is carried out under conditions that exceed the upper thermal limit (sample dimensions: 21 mm × 21 mm × 10 mm).
The result of the SLM when the process is carried out under conditions that exceed the upper thermal limit (sample dimensions: 21 mm × 21 mm × 10 mm).

Figure 15.

Plot of the operating window and results of simulation and experiments.
Plot of the operating window and results of simulation and experiments.

Figure 16.

The surfaces obtained through experiments carried out in conditions represented by points (1) and (2) in Fig. 15.
The surfaces obtained through experiments carried out in conditions represented by points (1) and (2) in Fig. 15.

Thermophysical properties and other parameters used in simulation_

Physical properties of the powder
Material densityρ8,600 kg/m3
Specific heat capacity solid phasecs390 J/kgoK
Specific heat capacity liquid phasecl410 J/kgoK
Latent heat of meltingLm334 [kJ/kg]
Melting temperatureTm1,380 °C
Boiling temperatureTb2,930 °C
Upper temperature marginΔTB30 °C
Emissivityε0.7
Process efficiency coefficientη0.27

j_tar-2023-0020_tab_003

APath cross-section area [m3]
CSpecific heat capacity [J/kg·K]
HPowder bed thickness [μm]
htTrack height [m]
LSpecific latent heat [J/kg]
keThermal effective conductivity of powder [W/mK]
kpTrack section profile coefficient [-]
PLaser beam power [W]
PdHatch spacing [μm]
reEffective laser beam radius [μm]
TmMelting temperature [K]
TbBoiling temperature [K]
TALower temperature limit [K]
TBUpper temperature limit [K]
VLaser scanning speed [mm/s]
WTrack width [m]
βPorosity
ρDensity [kg/m3]

Process parameters_

ParametersLower limitUpper limitUnit
Laser beam power70170W
Scanning speed1001,200mm/s
Powder layer thickness2535μm
DOI: https://doi.org/10.2478/tar-2023-0020 | Journal eISSN: 2545-2835
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Language: English
Page range: 18 - 32
Submitted on: Feb 8, 2023
Accepted on: Sep 11, 2023
Published on: Dec 8, 2023
Published by: ŁUKASIEWICZ RESEARCH NETWORK – INSTITUTE OF AVIATION
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
selective laser melting (SLM),
thermal limitation,
mathematical modeling,
simulation
Related subjects:
Engineering,
Introductions and overviews,
Engineering, other,
Geosciences,
Geosciences, other,
Materials sciences,
Materials sciences, other,
Physics,
Physics, other

© 2023 Jerzy Kozak, Tomasz Zakrzewski, Marta Witt, Martyna Dębowska-Wąsak, published by ŁUKASIEWICZ RESEARCH NETWORK – INSTITUTE OF AVIATION
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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