Sirris Materials Workshop - 5 december 2013 - Functional Graded Materials with Additive Manufacturing - Julien Magnien, Sirris

1. What you should know about FGM
Sirris Materials day 2013

2. Introduction
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Principle & description
History
Applications
Manufacturing methods
Pros and cons
Conclusions

3. Principle & description
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A Functionally Graded Material (FGM) is a substance in which properties,
composition and/or structure is not homogenous. There is a controlled
spatial distribution of these characteristics to optimize the part made of
this FGM.
Example with a turbine blade :
Erosion
& heat
=> Ceramic
on the
external
surface
Pressure
&
vibration
=> Metal
matrix
weight
=> Light weighted
core

4. Principle & description

FGM is composite 2.0 :
Composite
 Sharp interface
 Risk of delaminating
 Weakness and strength
everywhere
The whole part is a
bit ductile and a bit
hard, homogenously
FGM
 Smooth transition
 Very good bond
 Volume properties
distribution
 material adaptation for
specific application.
This region is largely
hard
This region is largely
ductile

5. History :
 FGM in Nature :
Bamboo fibre reinforced biocomposites: A review - H.P.S. Abdul Khalil, I.U.H. Bhat,
M.Jawaid, A. Zaidon, D. Hermawan, Y.S. Hadi - Materials & Design - Volume 42,
December 2012, Pages 353–368
http://www.britannica.com

6. History :
 First human FGM in 1985. challenge : 1000°C
temperature gradient over a thickness of only 10
mm :
Outside
Inside
1700°C
700°C
10 mm
http://en.wikipedia.org/wiki/Functionally_graded_material

7. Applications :
 Cutting tool :
Mitsubishi Carbide developed “Miracle
Indexable Inserts” : carbide substrate
Coated
http://www.mitsubishicarbide.com/mmc/en/product/pdf/b/b031g.pdf

8. Applications
 Architecture :

9. Applications
 Ballistic
http://www3.ntu.edu.sg

10. Applications :
 Articulated mechanical parts :
Biomimesis in Standford

11. Applications :
 Thermal choc resistant for thermal barrier FGM:

12. Applications :
 Tailored thermal conductivity property for thermal management :
 Heat removal in engine bloc
 Cooling of electrical components
 Definition of a ceramic (alumina foam)/metal
(aluminum) gradient. The ceramic is an insulator
which protects cold devices from heat and
aluminum drives heat away from hot devices

13. Applications :
 Graded porosity of bones implants for better bone recolonization :

14. Applications :
 Graded porosity for adapted mechanical behavior :

15. Applications :
 Functionally graded implants :
http://research.unt.edu/ises/advanced-metallic-materials

16. Applications :
 Constant dielectric characteristic over temperature:
5 layers/compositions
=> ~composite
21 layers/compositions,
same thickness => FGM
http://144.206.159.178/ft/677/43119/781575.pdf
21 layers/compositions,
variable thickness

17. Applications :
 Thermal dilatation in High-Intensity Discharge lamp :
http://www.toto.co.jp/E_Cera/lampparts/fgm_electrode.htm

18. Applications :
 Reduced electrical field stresses in power supply insulators :
Δ = 100 kV
uniform
FGM
http://ir.nul.nagoya-u.ac.jp/jspui/bitstream/2237/14528/1/1097.pdf

19. Applications
 Buffer section between 2 different materials :
Material distribution
in the FGM layer

20. Applications :
 Manufacturing of an ablation resistant SiC/C FGM:
Higher
number of
layers is
better for
residual
thermal
stresses
Linear
evolution is
better for
residual
thermal
stresses

21. Processing methods
 Classification :
Constitutive
Homogenizing
Segregating

22. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Stepwise change :
 Die compaction (powder stacking)
 Limited N° of layers (< 10, 1mm/layer)
 Discontinuous process
 Low productivity

23. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Stepwise change :
 Sheet lamination
 Complex shapes achievable
 Sheets are expansive (powder rolling or
tape casting -> “green” state)
 Assembly by hot pressing

24. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Stepwise change :
 Wet powder spraying :
 Coating on complex surface
 Layer thickness from 50 µm -> ~1 mm

25. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Stepwise change :
 Slurry dipping :
 Thin coating by dipping in different
baths.
 Suitable for series production.
 Enter porous body by capillarity.

26. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Stepwise change :
 Solid freeform processes :
 Hot powder-binder mixtures extruded in
a mixing nozzle.

27. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Continuous change :
 Gravity sedimentation:
 Material choice limited
 Inter-particles interaction in highly
loaded suspensions
 Simple and repeatable

28. Processing methods – powder metallurgy
 Formation of graded powder compact (green) :
 Continuous change :
 Electrophoretic deposition:
 Continuous change of suspensions
 Different electrophoretic mobility
 Risk of bubble entrapment
 Several mm thick

29. Processing methods – powder metallurgy
 Formation of graded powder compact (green)
 Continuous change :
 Thermal spraying :
 Gradient coating on existing parts
 “Mechanical” bond

30. Processing methods – powder metallurgy
 Melting processes :
 Laser/plasma cladding :
 Gradient coating on existing parts.
SIRRIS
Pure Inconel 718
SS 316L ->
Inconel 718
Pure SS
316L
Inconel 718 ->
SS 316L

31. Processing methods – powder metallurgy
 Melting processes :
 Centrifugal/sedimentation casting :
 Solubility or wetting problems
Review Fabrication of Functionally Graded
Materialsunder a Centrifugal Force
Yoshimi Watanabe and Hisashi Sato

32. Processing methods – powder metallurgy
 Melting processes :
 Controlled mold filling :
 FGM width controlled by the degree of
solidification of the first melt

33. Processing methods – powder metallurgy
 Melting processes :
 Infiltration processing :
 Preform (metallic foam, pre-sintered green
part,…) with porosity gradient
 Infiltration by lower melting component
 Open pores/wetting needed

34. Processing methods summary
Processing techniques for functionally graded materials - B. Kieback, A. Neubrand, H. Riedel – materials science
& engineering A - 2002

35. Software developments
 New file format to develop the famous “.stl”, with
its own standard : ASTM F2915-12
 “AMF” stands for “Additive Manufacturing Format”
 XML script
 Open source
 Volume capabilities for FGM or lattices
 A lot of characteristics can be selected for each
voxel such as color, texture, material, density,…
http://www.astm.org/Standards/F2915.htm
http://amf.wikispaces.com/

36. Software developments
 Another FGM software from the MIT : Spec2Fab
http://spec2fab.mit.edu/

37. Pros and Cons :
Pros
 Solution for incompatible
materials combinations
 Improve materials efficiency
 Increase part lifetime
Cons
 Processes hard to control
 Complex phenomenon occur
(shrinkage, dilution,
distortions,…)
 Expansive techniques

38. Conclusions
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FGM = composite 2.0
More efficient use of materials capabilities
Already in the industry
Applicable in every technological fields.
=> Thank you for your attention !