Off-diagonal elastic constant and sp2-bonded graphitic grain boundary in nanocrystalline-diamond thin films

Ogi, Hirotsugu; Nakamura, Nobutomo; Tanei, Hiroshi; Hirao, Masahiko; Ikeda, Ryuji; Takemoto, Mikio
June 2005
Applied Physics Letters;6/6/2005, Vol. 86 Issue 23, p231904
Academic Journal
This letter studies the relationship between the off-diagonal elastic constant C12 and bond configuration in nanocrystalline-diamond (NCD) thin films deposited by the nitrogen-doped chemical vapor deposition method. The film thickness was varied between 2.4 and 11.3 μm. The elastic constants were measured by resonant-ultrasound spectroscopy coupled with laser-Doppler interferometry. The diagonal elastic constants C11 and C44, and Young’s modulus in NCD films are smaller than those of the bulk polycrystalline diamond and microcrystalline-diamond (MCD) thin films, and they decrease as the film thickness decreases. However, the off-diagonal elastic constant of the NCD films is significantly larger than that of the bulk diamond, while that of the MCD films is smaller. Micromechanics calculations revealed that this exceptional enhancement of C12 occurs when the material includes randomly distributed thin graphitic plates in the isotropic diamond matrix. Thus, this result indicates that the NCD films consist of sp3-bonded diamond grains and sp2-bonded grain boundaries.


Related Articles

  • Origin of macrostrains and microstrains in diamond-SiC nanocomposites based on the core-shell model. Palosz, B.; Stelmakh, S.; Grzanka, E.; Gierlotka, S.; Nauyoks, S.; Zerda, T. W.; Palosz, W. // Journal of Applied Physics;Oct2007, Vol. 102 Issue 7, p074303 

    SiC-diamond nanocomposites were synthesized from nanodiamond and nanosilicon powders. A core-shell model of the composite nanocrystals was examined assuming that interatomic distances in the grain interior, the core, and at the surface shell (grain boundaries in nanocrystalline solids) are...

  • Thermomechanical stability of ultrananocrystalline diamond. Adiga, Vivekananda P.; Suresh, Sampath; Datta, Arindom; Carlisle, John A.; Carpick, Robert W. // Journal of Applied Physics;Mar2012, Vol. 111 Issue 5, p054913 

    We have measured mechanical stiffness and dissipation in ultrananocrystalline diamond (UNCD) from 63 K to 450 K using microcantilever resonators in a custom ultrahigh vacuum (UHV) atomic force microscope. UNCD exhibits a temperature coefficient of modulus that is found to be extremely low: -26...

  • Twinning partial multiplication at grain boundary in nanocrystalline fcc metals. Zhu, Y. T.; Wu, X. L.; Liao, X. Z.; Narayan, J.; Mathaudhu, S. N.; Kecskés, L. J. // Applied Physics Letters;7/20/2009, Vol. 95 Issue 3, p031909 

    Most deformation twins in nanocrystalline face-centered cubic (fcc) metals have been observed to form from grain boundaries. The growth of such twins requires the emission of Shockley partials from the grain boundary on successive slip planes. However, it is statistically improbable for a...

  • Anisotropic shock response of columnar nanocrystalline Cu. Sheng-Nian Luo; Germann, Timothy C.; Desai, Tapan G.; Tonks, Davis L.; Qi An // Journal of Applied Physics;Jul2010, Vol. 107 Issue 12, p123507 

    We perform molecular dynamics simulations to investigate the shock response of idealized hexagonal columnar nanocrystalline Cu, including plasticity, local shear, and spall damage during dynamic compression, release, and tension. Shock loading (one-dimensional strain) is applied along three...

  • Grain boundary effects on defect production and mechanical properties of irradiated nanocrystalline SiC. Jin, Enze; Niu, Li-Sha; Lin, Enqiang; Song, Xiaoxiong // Journal of Applied Physics;May2012, Vol. 111 Issue 10, p104322 

    Grain boundaries (GBs) are known to play an important role in determining the mechanical and functional properties of nanocrystalline materials. In this study, we used molecular dynamics simulations to investigate the effects of damaged GBs on the mechanical properties of SiC that is irradiated...

  • A combined dislocation–cohesive zone model for fracture in nanocrystalline materials. Liu, Yingguang; Zhou, Jianqiu; Shen, Tongde // Journal of Materials Research;2012, Vol. 27 Issue 4, p694 

    A combined dislocation–cohesive zone model was proposed to describe the fracture toughness of nanocrystalline (nc) materials. In the framework of the model, cohesive stress near crack tip initiates edge dislocations, which move to the opposite grain boundaries. The emitted dislocations...

  • Grain Boundary Sliding and Lattice Dislocation Emission in Nanocrystalline Materials under Plastic Deformation. Gutkin, M. Yu.; Ovid'ko, I. A.; Skiba, N. V. // Physics of the Solid State;Sep2005, Vol. 47 Issue 9, p1662 

    A theoretical model is proposed to describe the physical mechanisms of hardening and softening of nanocrystalline materials during superplastic deformation. According to this model, triple interface junctions are obstacles to glide motion of grain boundary dislocations, which are carriers of...

  • Thermal transport and grain boundary conductance in ultrananocrystalline diamond thin films. Angadi, Maki A.; Watanabe, Taku; Bodapati, Arun; Xiao, Xingcheng; Auciello, Orlando; Carlisle, John A.; Eastman, Jeffrey A.; Keblinski, Pawel; Schelling, Patrick K.; Phillpot, Simon R. // Journal of Applied Physics;6/1/2006, Vol. 99 Issue 11, p114301 

    Although diamond has the highest known room temperature thermal conductivity, k∼2200 W/m K, highly sp3 amorphous carbon films have k<15 W/m K. We carry out an integrated experimental and simulation study of thermal transport in ultrananocrystalline diamond (UNCD) films. The experiments show...

  • Transmission of phonons through grain boundaries in diamond films. Morelli, D.T.; Uher, C.; Robinson, C.J. // Applied Physics Letters;3/8/1993, Vol. 62 Issue 10, p1085 

    Examines the transmission of phonons through grain boundaries in high quality diamond films. Impact of grain boundaries and intragrain defects on heat conduction; Measurement of thermal conductivity to eliminate the effects of intragrain defects; Use of calibrated germanium resistance sensors...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics