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The Role of Surfaces in Superplasticity

  • D. H. Avery
  • J. M. Stuart
Part of the Sagamore Army Materials Research Conference Proceedings book series (SAMC, volume 14)

Abstract

The rate of neck growth in superplastic materials depends directly on surface irregularities and inversely on the strain rate sensitivity, m = (d lnσ/d lnε). High values of m reflect a substantial contribution of diffusional creep, which is inversely related to a power function of the grain size. The characteristic maxima in the m versus log ε curves is explained by the extension of the diffusional creep model to include a back stress, σo, which increases with impurity and inclusion content, and is greater in the rolling than in the transverse direction.

The Coble model of grain boundary diffusional creep is shown to be appropriate for the viscous component in lead-tin.

Keywords

High Strain Rate Rate Sensitivity Strain Rate Sensitivity Back Stress Diffusional Creep 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Backofen, W. A., Turner, I. R. and Avery, D. H., “Superplasticity in an Aluminum-Zinc Alloy,” ASM Trans, Quart., 57 (1964), 980.Google Scholar
  2. 2.
    Avery, D. H. and Backofen, W. A., “A Structural Basis for Superplasticity,” ASM Trans. Quart, 58 (1965), 551.Google Scholar
  3. 3.
    Nadai, A. and Manjoine, M. J., “High-Speed Tension Tests at Elevated Temperatures,” J. Appl. Mech., 8 (1941), A77.Google Scholar
  4. 4.
    Hart, E. W., “A Theory of the Tensile Test,” Acta Met., 15 (1967), 351.CrossRefGoogle Scholar
  5. 5.
    Alden, T. H. and Cline, H., “Rate Sensitive Deformation in Tin-Lead Alloys,” Trans. Met. Soc. AIME, 239 (1967), 710.Google Scholar
  6. 6.
    Underwood, E. E., “A Review of Superplasticity and Related Phenomena,” J. Metals, 14 (1962), 914.Google Scholar
  7. 7.
    Presnyakov, A. A. and Starikova, G. V., “The Relationship Between Rate of Deformation and Solid State Transformation as a Condition for the Occurrence of Superplasticity,” Russian Mining and Metallurgy (Inf. Consultants), 4 (1963), 95.Google Scholar
  8. 9.
    Nabarro, F. R. N., “Deformation of Crystals by the Motion of Single Ions,” Proc. Conf. on Strength of Solids, Phys. Soc. London, Camb., (1948), 75.Google Scholar
  9. 10.
    Herring, C., “Diffusional Viscosity of a Polycrystalline Solid,” J. Appl. Phys., 21 (1950), 437.CrossRefGoogle Scholar
  10. 11.
    Jones, R. B. and Johnson, R. H., “Discussion of ‘A Structural Basis for Superplasticity’ by D. H. Avery and W. A. Backofen,” ASM Trans. Quart., 59 (1966), 356.Google Scholar
  11. 12.
    Coble, R, L., “A Model for Boundary Diffusion Controlled Creep in Polycrystalline Materials,” J. Appl. Phys., 34 (1963), 1679.CrossRefGoogle Scholar
  12. 13.
    Packer, C. M. and Sherby, O. D., “An Interpretation of the Superplasticity Phenomenon in Two-Phase Alloys,” ASM Trans. Quart., 60 (1967), 21.Google Scholar
  13. 14.
    Hayden, H. W., Gibson, R. C., Merrick, H. F. and Brophy, J. H., “Superplasticity in the Ni-Fe-Cr System,” ASM Trans. Quart., 60 (1967), 3.Google Scholar
  14. 15.
    Jeffries and Archer, The Science of Metals (1924), 76.Google Scholar
  15. 16.
    Pearson, C. E., “The Viscous Properties of Extruded Eutectic Alloys of Lead-Tin and Bismuth-Tin,” J. Inst. Metals, 54 (1934), 111.Google Scholar
  16. 17.
    Alden, T. H., “The Origin of Superplasticity in the Sn-5%Bi Alloy,” Acta Met., 15 (1967), 469.CrossRefGoogle Scholar
  17. 18.
    Doyle, G., “Microstructural Behavior in the Superplastic Lead-Tin Eutectic,” S.B. Thesis, M.I.T. (1966).Google Scholar
  18. 19.
    Puttick, K. E. and King, R., “Boundary Slip in Bicrystals of Tin,” J. Inst. Metals, 80 (1951–52), 537.Google Scholar
  19. 20.
    Strutt, P. R., Lewis, A. M. and Gifkins, R. C., “Grain Boundary Sliding in Bicrystals of Pure Lead,” J. Inst. Metals, 93 (1964–65), 71.Google Scholar
  20. 21.
    Holt, D. L. and Backofen, W. A., “Superplasticity in the Al-Cu Eutectic Alloy,” ASM Trans. Quart., 59 (1966), 755.Google Scholar
  21. 22.
    Okkerse, B., “Self Diffusion in Lead,” Acta Met., 2 (1954), 551.CrossRefGoogle Scholar
  22. 23.
    Lange, W. and Bergner, D., “Measurement of Grain Boundary Self Diffusion in Polycrystalline Tin,” Phys. Stat. Sol., 2 (1962), 1410.CrossRefGoogle Scholar
  23. 24.
    Backofen, W. A., Avery, D. H., Lee, D. and Holt, D. L., “Deformation Processing of Anisotropic Metals,” Quart. Prog. Report #1, BUWEPS Contract NOw 66-0068-d (1965), 4.Google Scholar

References

  1. 1.
    Eg., D. Kingery, A. Review of the Stress-Strain-Time-Temperature Behavior of Ceramics, ASTM Special Tech. Pub. No. 325, 28 (1962).Google Scholar
  2. 2.
    H. W. Hayden, R. C. Gibson, H. F. Merrick, and J. H. Brophy, “Superplasticity in the Ni-Fe-Cr System,” Trans. ASM, 60 (1967).Google Scholar

Copyright information

© Syracuse University Press Syracuse, New York 1968

Authors and Affiliations

  • D. H. Avery
    • 1
  • J. M. Stuart
    • 1
    • 2
  1. 1.Brown UniversityProvidenceUSA
  2. 2.Illinois Institute of TechnologyUSA

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