Additive Manufacturing of Metal Matrix CompositesAdditive Manufacturing of Metal Matrix Composites | Introduction: The LMD process Powder nozzle simulation Melt pool simulation 22.10.2018
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Florian Wirth (IWF, ETH Zürich)
22.10.2018 1
Additive Manufacturing of Metal Matrix Composites
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Introduction: The LMD process Powder nozzle simulation Melt pool simulation
22.10.2018 2
Contents
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Introduction: The LMD process
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Laser beam maintains a melt pool Powder supply into the melt pool Feed motion of laser beam and powder jet Multiple overlapping weld beads form a layer/coating Multiple layers form a 3D part
22.10.2018 4
The Laser Metal Deposition (LMD) process
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Coating against corrosion/wear Repair Additive manufacturing of 3D parts
22.10.2018 5
Application
50 mm
mining power generationmaterial processing
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Powder nozzle simulation
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One sixth of the three-jet powder nozzle and the space below is modeled
Used modules Turbulent flow k-ɛ Transport of
concentrated species 3 gases: He, Ar, Air
Particle tracing
22.10.2018 7
Powder nozzle model
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Results: Oxygen concentration, powder jet
carrier gas 5 l/min He 5 l/min Ar 5 l/min Ar
shield gas 15 l/min Ar 15 l/min Ar 5 l/min Ar
O2
vol.
%
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Oxidation can be reduced by He instead of Ar as carrier gas Reduced carrier gas flow rate (often not possible) Powder nozzle design: Larger powder channel Ø
22.10.2018 9
Absorptivity measurement
0.40.45
0.50.55
0.60.65
0.7
5 10 15
abso
rptiv
ity
shield gas flow rate Ar [l/min]
0.40.45
0.50.55
0.60.65
0.7
5 l/min Ar 3.5 l/min Ar 5 l/min He
abso
rptiv
ity
carrier gas
ba
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Melt pool simulation
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Used modules (in the 1st step) Heat transfer Laminar flow
→ Surface tension, Marangoni effect Deformed geometry Boundary PDE
→ Tracing of freely deforming surface
2nd step Particle tracing Behavior of carbide
particles inside themelt pool
22.10.2018 11
Model overview
deformed geometry
pow
der /
lase
r be
am a
xis
xy
z
outlet
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Absorptivity Melt pool Solid material Powder
(Attenuation → from powder jetsimulation)
Powder particle densitydistribution (→ powder jet Ø)
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Crucial input data
10 mm
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Good agreement between experiment and simulation in the case of sufficient bonding and low dilution
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Validation
2 mm
9
11
13
15
10
12
14
16
1
5
3
7
2
8
6
4
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Metal powder is mixed with carbide particle powder
The melt pool flow has only a minor effect on the carbide particle distribution The homogeneity of the carbide particle distribution can be improved by a
shorter melt pool lifespan and a proper choice of the particle size22.10.2018 14
Additive Manufacturing of MMCs
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Aknowledgement
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