Nano Indentation Lecture2


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Nano Indentation Lecture2

  1. 1. Do Kyung Kim Department of Materials Science and Engineering KAIST, Korea Nanoindentation Lecture 2 Case Study
  2. 2. Applications of nanoindentation <ul><li>Mechanical characterization of nanostructures </li></ul><ul><li>Pressure-induced phase transformation </li></ul><ul><li>Thin film and MEMS structure – mechanical properties </li></ul><ul><li>Biomechanics </li></ul><ul><li>Newly Developed Technique </li></ul>
  3. 3. Mechanical Characterization of Nanostructures
  4. 4. Carbon Nanotube (1) <ul><li>Vertically aligned carbon nanotubes were prepared using PECVD method with different nickel catalyst thickness. </li></ul><ul><li>The nanoindentation on a VACNT forest consecutively bends nanotubes during the penetration of the indenter. </li></ul>Sample A Sample B Sample C Gleason, J Mech Phys Solids, 2003
  5. 5. Carbon Nanotube (2) <ul><li>The resistance of a VACNT forest to penetration is due to successive bending of nanotubes as the indenter encounters nanotubes </li></ul><ul><li>Superposition of interaction between the indenter and nanotubes encountered by the indenter during nanoindentation gives the total penetration resistance. </li></ul>Gleason, J Mech Phys Solids, 2003
  6. 6. Carbon Nanotube (2) <ul><li>Average f-p curve for the three samples from experiements </li></ul><ul><li>Sample C (high density, small length) Sample A, B (Same density) Sample A (Larger diameter and smaller length) </li></ul>Gleason, J Mech Phys Solids, 2003
  7. 7. Silver Nanowire (1) <ul><li>Silver nanowire-not single crystal but twinned-prepared from two silver solutions (AgNO3 and NaOH) and adhered onto glass slide. </li></ul><ul><li>Nanoindentation and imaging with same Berkovich indenter. </li></ul><ul><li>Penetration depth as low as 15 nm. (30 % of diameter) </li></ul>Caswell, Nano Letters, 2003
  8. 8. Silver Nanowire (2) <ul><li>Hardness 0.87 GPa / Elastic modulus 88 GPa </li></ul><ul><li>In good agreement with the nanoindentation value of bulk single crystal, 2 times higher than macroscale indentation results (indentation size effect) </li></ul><ul><li>This approach permits the direct machining of nanowires. </li></ul>Caswell, Nano Letters, 2003
  9. 9. ZnO and SnO2 nanobelt (1) <ul><li>The nanobelts were synthesized by thermal evaporation of oxide powder. </li></ul><ul><li>Indentation with maximum 300  N with loading rate 10  N/s </li></ul>Wang, APL, 2003
  10. 10. ZnO and SnO2 nanobelt (2) <ul><li>ZnO is a little softer than bulk single crystal. </li></ul><ul><li>The crack propagates along [101] and cleavage surface is (010). </li></ul>Wang, APL, 2003
  11. 11. Pressure-induced Phase Transformation
  12. 12. Silicon (1) <ul><li>Single crystal silicon undergoes phase transformation during indentation </li></ul><ul><li>A sudden displacement discontinuity referred to as a pop-in </li></ul><ul><li>Upon unloading, pop-out or kink pop-out happen, resulting from a sudden material expansion </li></ul>Gogotsi, J Mater Res, 2004
  13. 13. Silicon (2) <ul><li>The average pop-in pressure is determined from pure elastic loading assumption. </li></ul>Gogotsi, J Mater Res, 2004
  14. 14. Silicon (3) <ul><li>Single and multiple pop-in events occurred during indentation </li></ul><ul><li>These events could be due to either subsurface cracking, squeezing out of ductile materials or sudden dislocation burtst </li></ul>1 mN/s 5 mN/s Gogotsi, J Mater Res, 2004
  15. 15. Silicon (4) <ul><li>A great amount of a-Si, Si-III, or Si-XII is at deeper rather than shallower depths for a number of unloading conditions. </li></ul><ul><li>The results from different wavelength spectrum show a-Si, Si-III, or Si-XII exist below the surface. </li></ul><ul><li>Pop-in, out  Si-III or Si-XII and No pop-in, out  a-Si </li></ul>Gogotsi, J Mater Res, 2004
  16. 16. Germanium (1) <ul><li>Nanoindentation experiments were performed using Berkovich and cube-corner indenters </li></ul><ul><li>The unloading pop-out or elbow phenomena was not observed in loading curve. </li></ul><ul><li>A number of displacement discontinuities in the loading curve are caused by discontinuous crack extension and chipping. </li></ul>Pharr, APL, 2005
  17. 17. Germanium (2) <ul><li>SEM observation of the cube corner hardness impressions revealed a thin layer of extruded material. </li></ul><ul><li>The micro-Raman spectra for cube-corner indentation exhibits distinct narrow Ge-IV and a-Ge peaks. </li></ul><ul><li>Ge-IV phased vanishes within 20 hours of removing pressure. </li></ul>Pharr, APL, 2005
  18. 18. Thin Film and MEMS Structure – Mechanical Properties
  19. 19. MEMS structure (1) <ul><li>Silicon nanobeam fabricated by micromachining process </li></ul><ul><li>Load applied by indentation loading machine </li></ul><ul><li>Si strength-17.6 GPa (bulk single crystal strength 6 GPa) </li></ul><ul><li>Similar elastic modulus </li></ul>Li, Ultramicroscopy, 2003
  20. 20. MEMS structure (2) <ul><li>SiO2 microbeam fabrication by micromachining process </li></ul><ul><li>SiO2 strength 68 Gpa (18.5  m sample) / 2.5 Gpa (58.5  m sample) </li></ul>Lee, J Kor Ceram Soc, 2003
  21. 21. Thin films – Al (1) <ul><li>Aluminum single crystal (111) showing pop-in behavior </li></ul><ul><li>The maximum critical load 22  N  a mean pressure 14.7 GPa which is equivalent to a simplified estimate of the theoritical shear stress. </li></ul><ul><li>Dislocation is responsible for pop-in events. </li></ul>Moris Jr, J Mater Res, 2004
  22. 22. Thin films – Al (2) <ul><li>In situ nanoindentation </li></ul><ul><li>Approach  Contact  Plastic deformation  Extensive dislocation activity </li></ul>Moris Jr, J Mater Res, 2004
  23. 23. 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
  24. 24. Residual stress (1) <ul><li>Residual stress from </li></ul><ul><ul><li>non-uniform cooling down from the processing temperature </li></ul></ul><ul><ul><li>deposition of a surface coating or a thin film on a substrate </li></ul></ul><ul><li>Equal biaxial state of residual stress (tensile or compressive) </li></ul>Suresh, Acta Mater, 1998
  25. 25. Residual stress (2) <ul><li>Tensile </li></ul><ul><li>Compressive </li></ul>Suresh, Acta Mater, 1998
  26. 26. Residual stress (3) <ul><li>Implementation with ref. sample </li></ul>Suresh, Acta Mater, 1998
  27. 27. Superlattice (1) <ul><li>Nanscale multilayered coating </li></ul><ul><li>W/ZrN nanolayer </li></ul><ul><li>Superlattice period: 2.1 nm </li></ul><ul><li>Annealed at 1000  C for 1hr </li></ul><ul><li>AlN/VN nanolayer </li></ul><ul><li>Epitaxial stabilization of B1-AlN </li></ul><ul><li>Transformation to wurtzite </li></ul>Scott, MRS bulletin, 2003
  28. 28. Superlattice (2) <ul><li>Nanoindentation TiN/TiB2 superlattice </li></ul>Scott, MRS bulletin, 2003
  29. 29. Biomechanics
  30. 30. Dental hard tissue (1) Anisotropic structure of enamel Swain, J Mater Res, 2006
  31. 31. Dental hard tissue (1) <ul><li>Nanoindentation experiments on enamel with different orientation and indenter radius </li></ul><ul><li>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. </li></ul>
  32. 32. Dental hard tissue (3) <ul><li>The bacterial demineralization in enamel known as caries is simply detected through the changes in its mechanical properties. </li></ul>
  33. 33. Dental hard tissue (4) Weihs, Archives of Oral Biology, 2002 Nanoindentation mapping of enamel tooth structure Lingual Buccal Pulp Dentin Hardness (GPa) 2.5 3 3.5 4.0 4.5 5 5.5 6 Lingual Buccal Pulp Dentin Elastic Modulus (GPa) 110 100 90 80 70 60 50 120
  34. 34. Human bone (1) <ul><li>Human Femur – cortical and trabecula bone lamellae </li></ul>Goldstein, J Biomech, 1999
  35. 35. Human bone (2) <ul><li>The mean elastic modulus was found to be significantly influenced by the type of lamella and by donor. </li></ul><ul><li>Hardness followed a similar distribution as elastic modulus among types of lamellae and donor. </li></ul>Goldstein, J Biomech, 1999
  36. 36. Biocomposite (1) <ul><li>Hydroxyapatite (HA) + polymethylmethacrylate (PMMA) + co-polymer coupling agent </li></ul><ul><li>In vitro interfacial mechanics of HA and PMMA cross section of the composite </li></ul><ul><li>Microscopic analysis </li></ul><ul><li>Indentation analysis (load-displacement curve)  more comprehensive local analysis </li></ul><ul><li>In vitro testing – a reduction of bulk bending, local elastic modulus, local hardness with increase of immersion time </li></ul><ul><li>The effect of coupling agent  improvement of the interfacial mechanics </li></ul>Marcolongo, IEEE Bioeng, 2004
  37. 37. Biocomposite (2) <ul><li>Human bone </li></ul><ul><ul><li>45-60% mineral: HA </li></ul></ul><ul><ul><li>20-30% matrix: collagen </li></ul></ul><ul><ul><li>10-20% water </li></ul></ul>Marcolongo, IEEE Bioeng, 2004
  38. 38. Biocomposite (3) <ul><li>To determine the local mechanical properties of a bioactive composite a function of immersion period in simulated body fluid (SBF)  in vitro testing </li></ul>Marcolongo, IEEE Bioeng, 2004
  39. 39. Biocomposite (4) <ul><li>The “in vitro” local mechanical properties of the bioactive composite as a function of surface bioactivity </li></ul>Marcolongo, IEEE Bioeng, 2004
  40. 40. Newly Developed Technique
  41. 41. Cross-section of indentation damage(1) Indentation Pt Fast mill Tilt Markers Slow mill Lift-off Bradby, 2004 <ul><li>Focused ion beam TEM sample preparation </li></ul>
  42. 42. Cross-section of indentation damage(2) Fast unloading Slow unloading Slip line Misc. defect Extended defect Bradby, 2004 Silicon
  43. 43. Cross-section of indentation damage(3) GaAs InP Bradby, 2004
  44. 44. Cross-section of indentation damage(4) GaN ZnO Bradby, 2004
  45. 45. In-situ nanoindentation in SEM (1) Utke, 2006
  46. 46. In-situ nanoindentation in SEM (2) <ul><li>Vitreloy 105 (Zr 52.5 Cu 17.9 Ni 14.6 Al 10 Ti 5 ) </li></ul>Partial correlation between shear band formation and displacement burst in P-h curve. Utke, 2006
  47. 47. In-situ nanoindentation in SEM (3) <ul><li>FEB deposited reference pattern for in situ measure of contact area </li></ul>Utke, 2006
  48. 48. In-situ nanoindentation in SEM (4) Silicon pillar Median crack Basal crack Buckling Utke, 2006
  49. 49. In-situ nanoindentation in TEM (1) Minor, 2002
  50. 50. In-situ nanoindentation in TEM (2) Minor, 2002
  51. 51. In-situ nanoindentation in TEM (3) Before After Minor, 2002
  52. 52. Concluding remarks <ul><li>Broad applications of Nanoindentation to investigate the mechanical properties!!! </li></ul>