Student Research

Evaluation of the mechanical properties of common nanoscale contact geometries

Bill Mook, advisors: Bill Gerberich (CEMS), Joachim Heberlein (ME)

Research
My current research is focused on accounting for the effect of hydrostatic pressure on indentation modulus at nanoscale contacts.  Additional research has focused on characterizing the mechanical properties of freestanding nanostructures by nanoindentation.  Examples of tested structures include single crystal nanoparticles and polycrystalline nanoposts; both of which can be loaded in compression.  From these experiments I’ve developed methods to characterize the structures’ mechanical properties including (where applicable) their (i) effective elastic modulus as a function of pressure, (ii) flow stress, (iii) fracture toughness and (iv) activation volume necessary for plastic deformation.  Additional research has also focused on the characterization of hard, wear resistant films. 

As an intern at Sandia National Laboratory (Livermore) I was involved with research pertaining to thin film adhesion and mechanical integrity characterized by four-point beam bending tests, nanoscratch and nanoindentation techniques which included the first nanoindentation tests on MOF (metal organic framework) single crystals.  I also collaborated in the first in-situ compression test of a single crystal nanoparticle in a transmission electron microscope (TEM) equipped with a nanoindenter which showed cleavage-fracture of the nanoparticle. 

Figure for Mook Research

Figure Caption: Compression test of an aluminum nanopost showing (a) an contact-mode AFM image of a typical nanopost prior to compression and (b) the nanopost after compression. Typical load-displacement data of an aluminum nanopost compression can be seen in (c) while (d) shows both the load and displacement as a function of time where the load drop during the hold period can be clearly seen.  Both the structure’s flow stress and activation volume can be calculated from this data.

Selected Papers

  1. W.M. Mook, W.W. Gerberich, “The effect of hydrostatic pressure at nanoscale contacts,” accepted for MRS Fall Symposium AA Proceedings (2007).
  2. W.M. Mook, M.S. Lund, C. Leighton, W.W. Gerberich, “Flow stresses and activation volumes for highly deformed nanoposts,” Materials Science & Engineering A, accepted (2007).
  3. W.W. Gerberich, W.M. Mook, C.B. Carter, R. Ballarini, “A crack extension force correlation for hard materials,” Proceedings of the National Academy of Sciences, submitted (2007).
  4. D. Bahr, J. Reid, W.M. Mook, C. Bauer, R. Stumpf, A. Skulan, N.R. Moody, B.A. Simmons, M. Shindel, “Mechanical properties of cubic zinc carboxylate IRMOF-1 metal-organic framework crystals,” Physical Review B 76 (2007) 184106.
  5. M.J. Cordill, W.M. Mook, D. Farkas, W.W. Gerberich, “Novel Routes to Nanocrystalline Mechanical Characterization,” J. of Materials, submitted (2007).
  6. W.M. Mook, J.D. Nowak, C.R. Perrey, C.B. Carter, R. Mukherjee, S.L. Girshick, P.H. McMurry and W.W. Gerberich, “Compressive stress effects on nanoparticle modulus and fracture,” Physical Review B, 75 (2007) 214112.
  7. J.D. Nowak, W.M. Mook, A.M. Minor, W.W. Gerberich and C.B. Carter, "Fracturing a Nanoparticle," Philosophical Magazine, v 87, n 1 (2007) 29–37.
  8. J. Deneen, W.M. Mook, A. Minor, W.W. Gerberich, C.B. Carter, “In situ deformation of silicon nanospheres,” J. of Materials Science, 41 (2006) 4477–4483.
  9. W.W. Gerberich, W.M. Mook, M.J. Cordill, J.M. Jungk, B. Boyce, I. Friedmann, N.R. Moody, D. Yang, “Nanoprobing fracture length scales,” International Journal of Fracture, v 138, n 1-4 (2006) 75-100.
  10. W.W. Gerberich, W.M. Mook, M.D. Chambers, M.J. Cordill, C.R. Perrey, C.B. Carter, R.E. Miller, W.A. Curtin, R., Mukherjee and S.L. Girshick, “An energy balance criterion for nanoindentation-induced single and multiple dislocation events,” J. of Applied Mechanics,  v 73, n 2 (2006) 327-34.
  11. W.W. Gerberich, W.M. Mook, “News and Views: A new picture of plasticity.” Nature Materials, 4, August (2005) 577-578.
  12. F. Liao, S.L. Girshick, W.M. Mook, W.W. Gerberich, M.R. Zachariah, “Superhard nanocrystalline silicon carbide films,” Applied Physics Letters, v 86, n 17 (2005) 171913-1-3.
  13. W.W. Gerberich, M.J. Cordill, W.M. Mook, N.R. Moody, C.R. Perrey, C.B. Carter, R. Mukherjee and S.L. Girshick. “A boundary constraint energy balance criterion for small volume deformation.” Acta Materialia, v 53, n 8 (2005) 2215-29.
  14. W.W. Gerberich, W.M. Mook, M.J. Cordill, C.B. Carter, C.R. Perrey, J.V. Heberlein and S.L. Girshick, "Reverse plasticity in single crystal silicon nanospheres," International Journal of Plasticity 21 (2005) 2391-2405.
  15. J. Hafiz, X. Wang, R. Mukherjee, W.M. Mook, C.R. Perrey, J. Deneen, J.V.R. Heberlein, P.H. McMurry, W.W. Gerberich, C.B. Carter and S.L. Girshick, “Hypersonic plasma particle deposition of Si–Ti–N nanostructured coatings,” Surface & Coatings Technology, v. 188–189 (2004) 364–370.
  16. W.M. Mook, J.M Jungk, M.J. Cordill, N.R. Moody, Y. Sun, Y. Xia and W.W. Gerberich, "Geometry and surface state effects on the mechanical response of Au nanostructures," Zeitschrift für Metallkunde, vol. 95, n 6 (2004) 416-424.
  17. J.M. Jungk, W.M. Mook, M.J. Cordill, D.F. Bahr, J. Hoehn, M. Chambers and W.W. Gerberich, "A length scale based hardening model for ultra small volumes ", Journal of Materials Research vol. 19, n 10 (2004) 2812-2821.
  18. W.W. Gerberich and W.M. Mook, “De Petites Boules Tres Dures,” Pour la Science, vol. 41 (2003) 19 (French).
  19. W.W. Gerberich, W.M. Mook, C.R. Perrey, C.B. Carter, M.I. Baskes, R. Mukherjee, A. Gidwani, J. Heberlein, P.H. McMurry and S.L. Girshick , “Superhard Silicon Nanospheres,” Journal of the Mechanics and Physics of Solids, vol. 51 (2003) 979-992.