Dependence of confined plastic flow of polycrystalline Cu thin films on microstructure

Abstract

Axial compression was conducted on micro-pillars, in which polycrystalline Cu thin films were sandwiched between CrN and Si. Plastic flow of Cu was achieved, when the Cu films are inclined either at 90° or 45° with respect to the pillar axis. The texture of Cu films was altered by changing the template on which film growth occurred. The Cu microstructure was further altered by post-deposition annealing. The flow stress shows little dependence on the film texture in the as-deposited state. However, annealing influences the flow stress of confined Cu films significantly. The implications on strain gradient plasticity models are discussed.

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References

  1. 1.

    N.A. Fleck, G.M. Muller, M.F. Ashby, and J.W. Hutchinson: Strain gradient plasticity: theory and experiment. Acta Metall. Mater. 42, 475–487 (1994).

    CAS  Article  Google Scholar 

  2. 2.

    Q. Ma and D.R. Clarke: Size dependent hardness of silver single crystals. J. Mater. Res. 10, 853–863 (1995).

    CAS  Article  Google Scholar 

  3. 3.

    J.S. Stolken and A.G. Evans: A microbend test method for measuring the plasticity length scale. Acta Mater. 46, 5109–5115 (1998).

    CAS  Article  Google Scholar 

  4. 4.

    M.D. Uchic, D.M. Dimiduk, J.N. Florando, and W.D. Nix: Sample dimensions influence strength and crystal plasticity. Science 305, 986–989 (2004).

    CAS  Article  Google Scholar 

  5. 5.

    M.D. Uchic, P.A. Shade, and D.M. Dimiduk: Plasticity of micrometer-scale single crystals in compression. Annu. Rev. Mater. Res. 39, 361–386 (2009).

    CAS  Article  Google Scholar 

  6. 6.

    N.A. Fleck and J.W. Hutchinson: Strain gradient plasticity. Adv. Appl. Mech. 33, 295–361 (1997).

    Article  Google Scholar 

  7. 7.

    J.Y. Shu, N.A. Fleck, E. Van der Giessen, and A. Needleman: Boundary layers in constrained plastic flow: comparison of nonlocal and discrete dislocation plasticity. J. Mech. Phys. Solids 49, 1361–1395 (2001).

    Article  Google Scholar 

  8. 8.

    C.F. Niordson and J.W. Hutchinson: Basic strain gradient plasticity theories with application to constrained film deformation. J. Mech. Mater. Struct. 6, 395–416 (2011).

    Article  Google Scholar 

  9. 9.

    V.L. Tagarielli and N.A. Fleck: The shear response of a thin aluminum layer. J. Appl. Mech. 78, 014505/1-3 (2011).

  10. 10.

    Y. Mu, J.W. Hutchinson, and W.J. Meng: Micro-pillar measurements of plasticity in confined Cu thin films. Extreme Mech. Lett. 1, 62–69 (2014).

    Article  Google Scholar 

  11. 11.

    Y. Mu, K. Chen, and W.J. Meng: Thickness dependence of flow stress of Cu thin films in confined shear plastic flow. MRS Commun. 4, 129–133 (2014).

    CAS  Article  Google Scholar 

  12. 12.

    J.R. Greer, W.C. Oliver, and W.D. Nix: Size dependence of mechanical properties of gold at the micron scale in the absence of strain gradients. Acta Mater. 53, 1821–1830 (2005); Erratum, Acta Mater. 54, 1705 (2006).

    CAS  Article  Google Scholar 

  13. 13.

    W.J. Meng, T.J. Curtis, LE. Rehn, and P.M. Baldo: Temperature dependence of inductively coupled plasma assisted deposition of titanium nitride coatings. Surf. Coat. Technol. 120/121, 206–212 (1999).

    Article  Google Scholar 

  14. 14.

    J.P. Hirth and J. Lothe: Theory of Dislocations, 2nd ed. (Krieger Publishing, Malabar, FL, 1992).

    Google Scholar 

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Acknowledgment

Partial project supports from NSF OIA-1541079 and LA BoR LEQSF(2013-16)-RD-B-01 are gratefully acknowledged.

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Correspondence to W. J. Meng.

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Mu, Y., Zhang, X., Hutchinson, J.W. et al. Dependence of confined plastic flow of polycrystalline Cu thin films on microstructure. MRS Communications 6, 289–294 (2016). https://doi.org/10.1557/mrc.2016.20

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