le centre collectif de l’industrie technologique belge

Principle and applications

Potential of Functionally Graded Materials (FGM)

Summary

1. Small introduction to FGM and comparison with traditional composites

2. Actual applications of FGM in industry world 3. Existing processes to produces FGM and comparison 4. What’s up in AM world ?

12/4/2012 2

History :

• First concept in Japan 1984 :

The challenge was to use a combination of materials to build a thermal barrier on a space plane capable of withstanding a surface temperature of 2000K and a temperature gradient of 1000K across a 10 mm section

Source :

http://en.wikipedia.org/wiki/Functionally_graded_material

12/4/2012 3

The Principle :

• Make a graded material by varying the composition or microstructure from one material to another (or more), with a specific gradient. This enables the FGM to have the best properties of both materials where it is needed.

porous

dense

12/4/2012 4

http://users.telenet.be/jeffstubbe/thesis/documenten/papers/Mechanical%20properties%20of%20functionally%20graded%20hierarchical%20bamboo%20structures.pdf

Difference between composite and FGM

Composite • Sharp interface between materials,

so sharp properties change • Risk of delaminating under extreme

working conditions • Matrix with charge, so weakness

and strength of both materials are present everywhere

FGM • Smooth transition between materials • Very good bond between materials • spatial properties distribution is

possible • Possibility to tailor a material for

specific application.

12/4/2012 5

All the part is a bit thermal

conductive and the matrix lost a bit of

hardness

This region is largely hard

This region is largely thermal conductive

Mining

• cuttings rollers for tunneling are currently made of surface hardened 18CrNi8 steel. It is possible to increase their current lifetime (50 – 500 m into rocks) with a gradient of metal/WC

12/4/2012 6

Ductile and sufficiently deformation resistance towards high loading

Very hard surface with high ceramic content in ductile matrix

Power generation

• The steam flow is introduced in the turbine by stems valves. The corrosive environment ( water 500 – 600°C) need special material (high temperature strength, creep resistance, wear, corrosion)

12/4/2012 7

http://www.ge-energy.com/products_and_services/products/steam_turbines/mp_mc_series.jsp

High ceramic content

Ni super alloy

steam

http://www.ornl.gov/sci/oetd/documents/02086_c.pdf

Thermal dilatation

• Thermal dilatation in High-Intensity Discharge lamp

http://www.toto.co.jp/E_Cera/lampparts/fgm_electrode.htm

The challenge of ceramic/metal microcomposites and nanocomposites José S. Moya, Sonia Lopez-Esteban , Carlos Pecharromán – progress in materials science - 2007

12/4/2012 8

Aerospace

• Need to have good mechanical properties and light weight

http://www.msoe.edu/academics/research_centers/rpc/tetralattice.shtml

12/4/2012 9

A framework for object modeling - V. Kumara, D. Burnsb, D. Duttaa,*, C. Hoffmannc - Computer-Aided Design 31 (1999) 541–556

Tools

• Cutting tool insert with hard homogenous surface layer and core with intermediate graded layer

12/4/2012 10

http://www.mtm.kuleuven.be/Onderzoek/Ceramics/Materials#FGM

Mold Injection

• For injection molding, mold hardness and cooling are both important :

Cooling channel

Part injected

Copper : good thermal draining but poor mechanical properties

Nickel alloy: good mechanical properties but not enough heat removal

• 3-4 X Improvement in Heat Removal • Turbulence Inducing Form • High Projected Surface Area • High Compressive Strength • Conforms to Any Shape http://www.msoe.edu/academics/research_centers

/rpc/tetralattice.shtml

12/4/2012 11

Biomedical

• Functionally graded implant for cranial reconstruction

12/4/2012 12

http://nano.tu-dresden.de/forschung/TE/LitTE5.pdf

Biomedical

• Functionally graded implant for orthopedic implants

12/4/2012 13

http://research.unt.edu/ises/advanced-metallic-materials

Biomedical

• Dental implant with Functionally Graded Porosity

http://www.smu.edu/Lyle/Departments/ME/Research/RCAM/Laboratories/Rapid_Manufacturing/RMbyEBM/DentalImplants

12/4/2012 14

Die reinforcement

• Tool steel is largely used in die our tool manufacturing because relatively inexpensive but wear is a problem. Functionally graded materials and structures made from ferrous or nickel-based materials can customize the properties (hardness) of the tool where it is needed :

12/4/2012 15

http://www1.eere.energy.gov/manufacturing/industries_technologies/imf/pdfs/16941_functionally_graded_materials.pdf

Filtration

• It’s possible to change the mesh size to build a filter with graded pore size in 3D :

http://www.msoe.edu/academics/research_centers/rpc/tetralattice.shtml

12/4/2012 16

Dielectric component

• Gradient of BaTiO3–SrTiO3 is made by powder compaction to have a constant dielectric characteristic versus temperature.

5 layers/compositions => ~composite

21 layers/compositions, same thickness => FGM

21 layers/compositions, variable thickness

http://144.206.159.178/ft/677/43119/781575.pdf

12/4/2012 17

Power generation insulator

• The high electric field stress around solid insulator can be reduced on the electrode surface with contact to the solid dielectrics thanks to FGM.

12/4/2012 18

Δ = 100 kV

uniform

FGM

http://ir.nul.nagoya-u.ac.jp/jspui/bitstream/2237/14528/1/1097.pdf

Architecture

• “printing” concrete with variable density, producing structures that are both lighter and stronger than conventional concrete, by making it porous in the center and bulk on the exterior

12/4/2012 19

http://www.fluidynenz.250x.com/nov05/agwaste.html

http://www.shapeways.com/blog/archives/997-Variable-Density-3D-Printing-and-the-Potential-for-Architecture.html

Miscellaneous

• Defense : inhibit crack propagation in armor plate or penetration resistant material in bullet-proof vests.

• Energy : thermal barrier on turbine blade • Optoelectronics : graded refractive index material

12/4/2012 20

Different types depending on applications

Type Properties Processing Applications

Ceramic/metal bulk FGMs

Thermal stress relaxation; high heat resistance and wear

resistance, high mechanical strength

Spark plasma sintering process

High efficiency engine components

Titanium (alloys) with graded density or porosity

Combination of good mechanical properties and light weight

Additive, layer-wise process: direct metal laser sintering (DMLS) of powders

Light weight structures for aircraft and space industry, implants

Toolsteels with C, V, Cr gradients; steels or Ni

superalloys with ceramic (oxide, carbide) particle gradient

Combination of toughness and hardness or wear resistance

Additive, layer-wise process: 3D-printing with local material composition control (generating a green part of powdered material and sintering or infiltration)

Tools, medical instruments, implants, aircraft and space industry.

Functionally graded cemented carbide: titanium based surface ceramic layer, tough cemented carbide core and intermediate layer with graded composition

Wear resistance, breakage resistance, thermal crack

resistance

Powder sintering

Cutting insert

Ferritic-austenitic combinations like 316L and 17-4PH; steel-

ceramic combinations

Magnetic and non-magnetic; ductile and stiff and other

Co-injection moulding and co-sintering (building a graded interface)

Automotive industry, sensors; medical instruments

Precious metals like Pt, Ag (catalysis) and metal oxides like

SnO2 (sensors) with graded porosity from bulk to

nanometre scale

High specific surface and strong gas-metal interaction; graded porosity combines optimised

contact on substrates (bulk side) and high functionality (nano-

structured side)

PVD based on sputter techniques and inert gas evaporation and condensation, with in-

situ design of the deposed structures by controlling the process parameters

Gas sensors and catalytic active layers, low-temperature bonding for electronic

connections

http://kmm-vin.eu-vri.eu/home.aspx?lan=230&tab=194&itm=197&pag=202

12/4/2012 21

Different processing techniques • Processing techniques for functionally graded materials - B. Kieback, A. Neubrand, H. Riedel –

materials science & engineering A - 2002

12/4/2012 22

The future of FGM with AM processes ?

• A new standard is arriving to replace traditional STL files (Standard Triangulation Language). It is called AMF for “Additive Manufacturing Format”, ASTM F2915-12 :

Open source XML-based Triangles mesh with characteristics (colours, texture, material,…) with

voxels and functional representations (allowing lattice structure or FGM)

12/4/2012 23

0 1.25 0 1.75 0 1 1.25 1.5 1.75 2 0 1.25 0 1.75 0 1 1.25 1.5 1.75 2

Playing on “material” characteristic of voxels: 0 = “void” material 1 = bleu material 2 = orange material

http://www.astm.org/Standards/F2915.htm

http://amf.wikispaces.com/

Conclusion :

• Functionally graded material is an improvement of traditional composites which increases their strength and reduces their weakness.

• FGM can be used in every technological field. • Additive manufacturing techniques such as laser cladding or

plasma welding seem to be very suitable to start developing these new materials and deal with them in an accurate way to produce parts with well distributed properties.

=> Thank you for your attention !

12/4/2012 24