Abstract
The stability of crystal structures in multilayers of titanium and aluminum is influenced markedly by the bilayer thickness. Thus, as the bilayer thickness is decreased, the crystal structure of the titanium layers changes from hexagonal close-packed (hcp) to face-centered cubic (fcc) and then reverts back to hcp. In the case of the aluminum layers, there is a transition from fcc to hcp structure at very small values of the bilayer thickness. The reasons for these variations are not well understood, but they may well be influenced by the variation of stacking fault potentials. Nano-indentation has been used to derive the elementary mechanical properties of these multilayers, namely the Young’s modulus and hardness. No super-modulus effect is observed as the bilayer thickness is reduced. The hardness values increase markedly as the bilayer thickness is reduced, following a Hall-Petch relationship with this parameter.
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E. Esaki and R. Tsu, IBM Journal of Research & Development, 14 (1970), p. 61.
M. Piecuch and L. Nevot, Materials Science Forums, 59 & 60 (1990), p. 93.
P. Dhez and C. Weisbuch, ed., Physics, Fabrication and Applications of Multilayered Structures (New York: Plenum Press, 1988).
T. Shinjo and T. Takada, ed., Metallic Superlattices—Artificially Layered Structures. Studies in Physical and Theoretical Chemistry (Amsterdam, the Netherlands: Elsevier, 1987).
R. Ahuja, Ph.D. thesis, the Ohio State University (1994).
J.H. Underwood and T.W. Barbee, “Layered Synthetic Microstructures as Bragg Diffractors for X-Rays and Extreme Ultraviolet: Theory and Predicted Performance,” Applied Optics, 20 (1981), p. 3027.
B.Y. Jin and J.B. Ketterson, “Artificial Metallic Superlattices,” Advances in Physics, 38 (1988), p. 189.
R.C. Cammarata, “The Supermodulus Effect in Compositionally Modulated Thin Films,” Scripta Metallurgica, 20 (1986), p. 479.
D. Baral, J.B. Ketterson, and J.E. Hilliard, “Mechanical Properties of Composition-Modulated Cu-Ni Foils,” J. Applied Physics, 57,4 (1985), p. 1076.
G.E. Henein and J.E. Hilliard, “Elastic Modulus in Composition-Modulated Silver-Palladium and Copper-Gold Foils,” J. Applied Physics, 54,2 (1983), p. 728.
T. Tsakalakos and J.E. Hilliard, “Elastic Modulus in Composition-Modulated Copper-Nickel Foils,” J. Applied Physics, 54,2 (1983), p. 734.
A.L. Greer, “Atomic Diffusion and Phase Transformations in Artificially Layered Thin Films,” Scripta Metallurgica, 20 (1986), p. 457.
A.L. Greer and F. Spaepen, “Diffusion,” Synthetic Modulated Structure, ed. L.L. Chang and B.C. Giessen (New York: Academic Press, 1985), p. 419.
CM. Falco and I.K. Schuller, “Electronic and Magnetic Properties of Metallic Superlattices,” Synthetic Modulated Structures, ed. L.L. Chang and B.C. Giessen (London: Academic Press, 1985).
W.P. Lowe and T.H. Geballe, “Nb-Zr Multilayers: Structure & Superconductivity,” Physical Review B, 29,9 (1984), p. 4961.
Roy Clarke et al., “Stacking Structure and Superconductivity in Ru/Ir Bicrystal Superlattices,” Physical Review B, 34,3 (1986), p. 2022.
J.E. Cunnigham, J. Dura, and C.P. Flynn, “Coherent Bicrystal Superlattices: The Ir-Ru System,” Metallic Multilayers and Epitaxy, ed. M. Hong, D.U. Gubser, and S.A. Wolf (Warrendale, PA: TMS, 1987).
A. Bourret, and J.L. Rouviere, “Atomic Structure of Ion-Sputtered Fe/Ti Multilayers Studied by HREM,” Phil. Mag. B, 62,4 (1990), p. 415.
A.F. Jankowski and M.A. Wall, “Formation of a Face-Centered Cubic Titanium on a Ni Single Crystal and in Ni/Ti Multilayers,” J. Materials Research, 9,1 (1994), p. 31.
F.J. Lamelas et al., “Coherent fcc Stacking in Epitaxial Co/Cu Superlattices,” Physical Review B, 40,8 (1989), p. 5837.
J.A. Thornton, “High Rate Thick Film Growth,” Ann. Rev. Mater. Sci., 7 (1977), p. 239.
E.E. Fullerton, I.K. Schuller, and Y. Bruynseraede, “Quantitative X-Ray Diffraction from Superlattices,” MRS Bulletin (December 1992), p. 33.
A.C. Redfield and A.M. Zangwill, “Stacking Sequence in Close-Packed Metallic Superlattices,” Physical Review B, 34,2 (1986), p. 1378.
R.R. Ahuja, R. Bannerjee, and H.L. Fraser, manuscript in preparation.
G.M. Pharr and W.C. Oliver, “Measurement of Thin Film Mechanical Properties Using Nanoindentation,” MRS Bulletin, 17 (7) (1992), p. 28.
W.C. Oliver, B.N. Lucas, and G.M. Pharr, “Mechanical Characterization Using Indentation Experiments,” Mechanical Properties and Deformation Behavior of Materials Having Ultra-Fine Microstructures, ed. M. Nastasi et al. (New York: Elsevier, 1993).
W.C. Oliver and G.M. Pharr, “An Improved Technique for Determining Hardness and Elastic Modulus Using Load and Displacement Sensing Indentation Experiments,” J. Materials Research, 7,6 (1992), p. 1564.
P.M. Sargeant, Microindentation Techniques in Materials Science and Engineering, ed. P.J. Balu and B.R. Lawn (Philadelphia, PA: ASTM, 1986).
D. Tabor, in Ref. 28.
N.A. Fletch et al., “Strain Gradient Plasticity: Theory and Experiment,” Acta Met., 42,2 (1994), p. 475.
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Ahuja, R., Fraser, H.L. Structure and mechanical properties of nanolaminated Ti-Al thin films. JOM 46, 35–39 (1994). https://doi.org/10.1007/BF03222606
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DOI: https://doi.org/10.1007/BF03222606