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Nanoindentation Lecture 2 Case Study Do Kyung Kim Department of Materials Science and Engineering KAIST, Korea

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Page 1: Nano Indentation Lecture2

NanoindentationLecture 2 Case Study

Do Kyung Kim

Department of Materials Science and EngineeringKAIST, Korea

Page 2: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Applications of nanoindentation

• Mechanical characterization of nanostructures

• Pressure-induced phase transformation

• Thin film and MEMS structure – mechanical properties

• Biomechanics

• Newly Developed Technique

Page 3: Nano Indentation Lecture2

Mechanical Characterization of Nanostructures

Page 4: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Carbon Nanotube (1)

• Vertically aligned carbon nanotubes were prepared using PECVD method with different nickel catalyst thickness.

• The nanoindentation on a VACNT forest consecutively bends nanotubes during the penetration of the indenter.

Sample ASample A Sample BSample B

Sample CSample C

Gleason, J Mech Phys Solids, 2003

Page 5: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Carbon Nanotube (2)

• The resistance of a VACNT forest to penetration is due to successive bending of nanotubes as the indenter encounters nanotubes

• Superposition of interaction between the indenter and nanotubes encountered by the indenter during nanoindentation gives the total penetration resistance.

Gleason, J Mech Phys Solids, 2003

Page 6: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Carbon Nanotube (2)

• Average f-p curve for the three samples from experiements

• Sample C (high density, small length)Sample A, B (Same density)Sample A (Larger diameter and smaller length)

Gleason, J Mech Phys Solids, 2003

Page 7: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Silver Nanowire (1)

• Silver nanowire-not single crystal but twinned-prepared from two silver solutions (AgNO3 and NaOH) and adhered onto glass slide.

• Nanoindentation and imaging with same Berkovich indenter.• Penetration depth as low as 15 nm. (30 % of diameter)

Caswell, Nano Letters, 2003

Page 8: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Silver Nanowire (2)

• Hardness 0.87 GPa / Elastic modulus 88 GPa• In good agreement with the nanoindentation value of bulk single crys

tal, 2 times higher than macroscale indentation results (indentation size effect)

• This approach permits the direct machining of nanowires.

Caswell, Nano Letters, 2003

Page 9: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

ZnO and SnO2 nanobelt (1)

• The nanobelts were synthesized by thermal evaporation of oxide powder.

• Indentation with maximum 300 N with loading rate 10 N/s

Wang, APL, 2003

Page 10: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

ZnO and SnO2 nanobelt (2)

• ZnO is a little softer than bulk single crystal.

• The crack propagates along [101] and cleavage surface is (010).

Wang, APL, 2003

Page 11: Nano Indentation Lecture2

Pressure-induced Phase Transformation

Page 12: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Silicon (1)

• Single crystal silicon undergoes phase transformation during indentation

• A sudden displacement discontinuity referred to as a pop-in

• Upon unloading, pop-out or kink pop-out happen, resulting from a sudden material expansion Gogotsi, J Mater Res, 2004

Page 13: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Silicon (2)

• The average pop-in pressure is determined from pure elastic loading assumption.

Gogotsi, J Mater Res, 2004

Page 14: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Silicon (3)

• Single and multiple pop-in events occurred during indentation• These events could be due to either subsurface cracking, squeezing

out of ductile materials or sudden dislocation burtst

1 mN/s 5 mN/s

Gogotsi, J Mater Res, 2004

Page 15: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Silicon (4)

• A great amount of a-Si, Si-III, or Si-XII is at deeper rather than shallower depths for a number of unloading conditions.

• The results from different wavelength spectrum show a-Si, Si-III, or Si-XII exist below the surface.

• Pop-in, out Si-III or Si-XII and No pop-in, out a-SiGogotsi, J Mater Res, 2004

Page 16: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Germanium (1)

• Nanoindentation experiments were performed using Berkovich and cube-corner indenters

• The unloading pop-out or elbow phenomena was not observed in loading curve.

• A number of displacement discontinuities in the loading curve are caused by discontinuous crack extension and chipping.

Pharr, APL, 2005

Page 17: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Germanium (2)

• SEM observation of the cube corner hardness impressions revealed a thin layer of extruded material.

• The micro-Raman spectra for cube-corner indentation exhibits distinct narrow Ge-IV and a-Ge peaks.

• Ge-IV phased vanishes within 20 hours of removing pressure.

Pharr, APL, 2005

Page 18: Nano Indentation Lecture2

Thin Film and MEMS Structure – Mechanical Properties

Page 19: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

MEMS structure (1)

• Silicon nanobeam fabricated by micromachining process

• Load applied by indentation loading machine

• Si strength-17.6 GPa (bulk single crystal strength 6 GPa)

• Similar elastic modulus

Li, Ultramicroscopy, 2003

Page 20: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

MEMS structure (2)

• SiO2 microbeam fabrication by micromachining process• SiO2 strength 68 Gpa (18.5 m sample) / 2.5 Gpa (58.5 m sample)

Lee, J Kor Ceram Soc, 2003

Page 21: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Thin films – Al (1)

• Aluminum single crystal (111) showing pop-in behavior• The maximum critical load 22 N a mean pressure 14.7 GPa whic

h is equivalent to a simplified estimate of the theoritical shear stress.• Dislocation is responsible for pop-in events.

Moris Jr, J Mater Res, 2004

Page 22: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Thin films – Al (2)

• In situ nanoindentation • Approach Contact Plastic deformation Extensive dislocation activity

Moris Jr, J Mater Res, 2004

Page 23: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Thin films – Al (3)

Before indentation

After indentation with same direction

After indentation with tilted direction(dislocation in entire grain)

Moris Jr, J Mater Res, 2004

Page 24: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Residual stress (1)

• Residual stress from– non-uniform cooling down from the processing temperature– deposition of a surface coating or a thin film on a substrate

• Equal biaxial state of residual stress (tensile or compressive)

Suresh, Acta Mater, 1998

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Nano Ceramics Research Laboratory

Residual stress (2)

• Tensile • Compressive

Suresh, Acta Mater, 1998

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Nano Ceramics Research Laboratory

Residual stress (3)

• Implementationwith ref. sample

Suresh, Acta Mater, 1998

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Nano Ceramics Research Laboratory

Superlattice (1)

• W/ZrN nanolayer• Superlattice period: 2.1 nm• Annealed at 1000 C for 1hr

• AlN/VN nanolayer• Epitaxial stabilization of B1-AlN• Transformation to wurtzite

Scott, MRS bulletin, 2003

• Nanscale multilayered coating

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Nano Ceramics Research Laboratory

Superlattice (2)

• Nanoindentation TiN/TiB2 superlattice

Scott, MRS bulletin, 2003

Page 29: Nano Indentation Lecture2

Biomechanics

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Nano Ceramics Research Laboratory

Dental hard tissue (1)

Anisotropic structure of enamel

Swain, J Mater Res, 2006

Page 31: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Dental hard tissue (1)

• Nanoindentation experiments on enamel with different orientation and indenter radius

• Parallel to enamel rods, the hardness and modulus are 3.9 Gpa and 87.5 GPa, respectively , whereas perpendicular to enamel rods, they are 3.3 GPa and 72.2 GPa.

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Nano Ceramics Research Laboratory

Dental hard tissue (3)

• The bacterial demineralization in enamel known as caries is simply detected through the changes in its mechanical properties.

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Nano Ceramics Research Laboratory

Dental hard tissue (4)

LingualBuccal

Pulp

Dentin

Hardness (GPa)

2.5

3

3.5

4.0

4.5

5

5.5

6 LingualBuccal

Pulp

Dentin

Elastic Modulus (GPa)

110

100

90

80

70

60

50

120

Weihs, Archives of Oral Biology, 2002

Nanoindentation mapping of enamel tooth structure

Page 34: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Human bone (1)

• Human Femur – cortical and trabecula bone lamellae

Goldstein, J Biomech, 1999

Page 35: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Human bone (2)

• The mean elastic modulus was found to be significantly influenced by the type of lamella and by donor.

• Hardness followed a similar distribution as elastic modulus among types of lamellae and donor.

Goldstein, J Biomech, 1999

Page 36: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Biocomposite (1)

• Hydroxyapatite (HA) + polymethylmethacrylate (PMMA) + co-polymer coupling agent

• In vitro interfacial mechanics of HA and PMMA cross section of the composite

• Microscopic analysis• Indentation analysis (load-displacement curve) more comprehensi

ve local analysis• In vitro testing – a reduction of bulk bending, local elastic modulus, l

ocal hardness with increase of immersion time• The effect of coupling agent improvement of the interfacial mecha

nics

Marcolongo, IEEE Bioeng, 2004

Page 37: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Biocomposite (2)

• Human bone– 45-60% mineral: HA– 20-30% matrix:

collagen– 10-20% water

Marcolongo, IEEE Bioeng, 2004

Page 38: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Biocomposite (3)

• To determine the local mechanical properties of a bioactive composite a function of immersion period in simulated body fluid (SBF) in vitro testing

Marcolongo, IEEE Bioeng, 2004

Page 39: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Biocomposite (4)

• The “in vitro” local mechanical properties of the bioactive composite as a function of surface bioactivity

Marcolongo, IEEE Bioeng, 2004

Page 40: Nano Indentation Lecture2

Newly Developed Technique

Page 41: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Cross-section of indentation damage(1)

• Focused ion beam TEM sample preparation

Indentation Pt Fast mill

Tilt Markers Slow mill

Lift-off

Bradby, 2004

Page 42: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Cross-section of indentation damage(2) Fast unloading Slow unloading

Slip line

Misc. defect

Extended defect

Bradby, 2004

Silicon

Page 43: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Cross-section of indentation damage(3)

GaAs

InP

Bradby, 2004

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Nano Ceramics Research Laboratory

Cross-section of indentation damage(4)

GaN

ZnO

Bradby, 2004

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Nano Ceramics Research Laboratory

In-situ nanoindentation in SEM (1)

Utke, 2006

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Nano Ceramics Research Laboratory

In-situ nanoindentation in SEM (2)

• Vitreloy 105 (Zr52.5Cu17.9Ni14.6Al10Ti5)

Partial correlation between shear band formation and displacement burst in P-h curve.

Utke, 2006

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Nano Ceramics Research Laboratory

In-situ nanoindentation in SEM (3)

• FEB deposited reference pattern for in situ measure of contact area

Utke, 2006

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Nano Ceramics Research Laboratory

In-situ nanoindentation in SEM (4)

Silicon pillar

Median crack Basal crack Buckling

Utke, 2006

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Nano Ceramics Research Laboratory

In-situ nanoindentation in TEM (1)

Minor, 2002

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Nano Ceramics Research Laboratory

In-situ nanoindentation in TEM (2)

Minor, 2002

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Nano Ceramics Research Laboratory

In-situ nanoindentation in TEM (3)

Before After

Minor, 2002

Page 52: Nano Indentation Lecture2

Nano Ceramics Research Laboratory

Concluding remarks

• Broad applications of Nanoindentation to investigate the mechanical properties!!!