Nanoindentation Lecture 2 Case Study Do Kyung Kim Department of Materials Science and Engineering KAIST, Korea
NanoindentationLecture 2 Case Study
Do Kyung Kim
Department of Materials Science and EngineeringKAIST, Korea
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
Mechanical Characterization of Nanostructures
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
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
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
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
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
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
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
Pressure-induced Phase Transformation
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
Nano Ceramics Research Laboratory
Silicon (2)
• The average pop-in pressure is determined from pure elastic loading assumption.
Gogotsi, J Mater Res, 2004
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
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
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
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
Thin Film and MEMS Structure – Mechanical Properties
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
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
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
Nano Ceramics Research Laboratory
Thin films – Al (2)
• In situ nanoindentation • Approach Contact Plastic deformation Extensive dislocation activity
Moris Jr, J Mater Res, 2004
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
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
Nano Ceramics Research Laboratory
Residual stress (2)
• Tensile • Compressive
Suresh, Acta Mater, 1998
Nano Ceramics Research Laboratory
Residual stress (3)
• Implementationwith ref. sample
Suresh, Acta Mater, 1998
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
Nano Ceramics Research Laboratory
Superlattice (2)
• Nanoindentation TiN/TiB2 superlattice
Scott, MRS bulletin, 2003
Biomechanics
Nano Ceramics Research Laboratory
Dental hard tissue (1)
Anisotropic structure of enamel
Swain, J Mater Res, 2006
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.
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.
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
Nano Ceramics Research Laboratory
Human bone (1)
• Human Femur – cortical and trabecula bone lamellae
Goldstein, J Biomech, 1999
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
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
Nano Ceramics Research Laboratory
Biocomposite (2)
• Human bone– 45-60% mineral: HA– 20-30% matrix:
collagen– 10-20% water
Marcolongo, IEEE Bioeng, 2004
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
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
Newly Developed Technique
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
Nano Ceramics Research Laboratory
Cross-section of indentation damage(2) Fast unloading Slow unloading
Slip line
Misc. defect
Extended defect
Bradby, 2004
Silicon
Nano Ceramics Research Laboratory
Cross-section of indentation damage(3)
GaAs
InP
Bradby, 2004
Nano Ceramics Research Laboratory
Cross-section of indentation damage(4)
GaN
ZnO
Bradby, 2004
Nano Ceramics Research Laboratory
In-situ nanoindentation in SEM (1)
Utke, 2006
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
Nano Ceramics Research Laboratory
In-situ nanoindentation in SEM (3)
• FEB deposited reference pattern for in situ measure of contact area
Utke, 2006
Nano Ceramics Research Laboratory
In-situ nanoindentation in SEM (4)
Silicon pillar
Median crack Basal crack Buckling
Utke, 2006
Nano Ceramics Research Laboratory
In-situ nanoindentation in TEM (1)
Minor, 2002
Nano Ceramics Research Laboratory
In-situ nanoindentation in TEM (2)
Minor, 2002
Nano Ceramics Research Laboratory
In-situ nanoindentation in TEM (3)
Before After
Minor, 2002
Nano Ceramics Research Laboratory
Concluding remarks
• Broad applications of Nanoindentation to investigate the mechanical properties!!!