- Physical Review Journals
All JournalsPhysics Magazine
Access Provided by Xinjiang University

Physical Review Applied

Export citation

Export citation

Choose format for download:

Download Citation
  • Access by Xinjiang University

Mechanical Characterization of Impact-Induced Dynamically Recrystallized Nanophase

D. Rittel*, L. H. Zhang, and S. Osovski

  • Faculty of Mechanical Engineering, Technion, 32000 Haifa, Israel

  • *Corresponding author. merittel@technion.ac.il
PDF

Phys. Rev. Applied 7, 044012 – Published 19 April, 2017

DOI: https://doi.org/10.1103/PhysRevApplied.7.044012

Abstract

Dynamic failure of impact-loaded structures is often caused by dynamic shear localization, that is also known as adiabatic shear banding (ASB). While ASB has long been thought to be triggered by thermal softening, another potent softening mechanism has been recently identified in which islands of dynamically recrystallized nanograins nucleate and coalesce, ultimately leading to fracture. However, the exact nature and extent of the softening has not yet been characterized experimentally. Ti-6Al-4V is chosen as a model material to study the influence of impact-induced dynamic recrystallization (DRX) on the subsequent quasistatic flow properties through a systematic combination of dynamic tests up to a predefined level of strain followed by static testing to fracture. With the dynamic prestrain, the subsequent quasistatic yield strength of the material increases, while the strain-hardening capacity decreases noticeably once the relative dynamic prestrain level exceeds 0.5. Those observations, which are supported by transmission-electron-microstructural characterization, confirm not only the early formation of dynamically recrystallized islands reported by D. Rittel et al. [Phys. Rev. Lett. 101, 165501 (2008)], but mostly the influence this sparse phase has on the bulk mechanical response. In that respect, the present experiments confirm previously reported trends for other bulk nanograined materials, namely, elevation of the yield stress, significant drop in the strain hardening, and enhanced tendency for shear localization. The first two effects are clearly observed for the sparse islands of DRX that form in the bulk impacted material and allow for future modeling of the response of such hierarchical microstructures composed of both ultrafine and coarse grains.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (34)

  1. B. Dodd and Y. Bai, Adiabatic Shear Localization: Frontiers and Advances (Elsevier, New York, 2012).
  2. T. Altan and A. E. Tekkaya, Sheet Metal Forming: Processes and Applications (ASM International, Materials Park, OH, 2012).
  3. T. Childs, in CIRP Encyclopedia of Production Engineering (Springer, New York, 2014), pp. 27–33.
  4. Y. L. Bai, Thermo-plastic instability in simple shear, J. Mech. Phys. Solids 30, 195 (1982).
  5. Y. Me-Bar and D. Shechtman, On the adiabatic shear of Ti6Al4V ballistic targets, Mater. Sci. Eng. 58, 181 (1983).
  6. A. Marchand and J. Duffy, An experimental study of the formation process of adiabatic shear bands in a structural steel, J. Mech. Phys. Solids 36, 251 (1988).
  7. E. L. Thomas, Opportunities in Protection Materials Science and Technology for Future Army Applications (The National Academies Press, Washington, DC, 2011).
  8. H. Tresca, Sur la fluidité et l’écoulement des corps solides, Ann. Conserv. Arts Métiers 4 (1879).
  9. W. S. Farren and G. I. Taylor, The heat developed during plastic extension of metals, Proc. R. Soc. A 107, 422 (1925).
  10. G. I. Taylor and H. Quinney, The latent energy remaining in a metal after cold working, Proc. R. Soc. A 143, 307 (1934).
  11. C. Zener and J. H. Hollomon, Effect of strain rate upon plastic flow of steel, J. Appl. Phys. 15, 22 (1944).
  12. D. Rittel, Z. G. Wang, and M. Merzer, Adiabatic Shear Failure and Dynamic Stored Energy of Cold Work, Phys. Rev. Lett. 96, 0075502 (2006).
  13. D. Rittel and Z. G. Wang, Thermo-mechanical aspects of adiabatic shear failure of AM50 and Ti6Al4V alloys, Mech. Mater. 40, 629 (2008).
  14. D. Rittel, P. Landau, and A. Venkert, Dynamic Recrystallization as a Potential Cause for Adiabatic Shear Failure, Phys. Rev. Lett. 101, 165501 (2008).
  15. P. Landau, S. Osovski, A. Venkert, V. Gärtnerová, and D. Rittel The genesis of adiabatic shear bands, Sci. Rep. 6, 37226 (2016).
  16. E. Bouchbinder and J. S. Langer, Nonequilibrium thermodynamics of driven amorphous materials. III. Shear-transformation-zone plasticity, Phys. Rev. E 80, 1 (2009).
  17. S. Osovski, D. Rittel, P. Landau, and A. Venkert, Microstructural effects on adiabatic shear band formation, Scr. Mater. 66, 9 (2012).
  18. D. Jia, Y. M. Wang, K. T. Ramesh, E. Ma, Y. T. Zhu, and R. Z. Valiev Deformation behavior and plastic instabilities of ultrafine-grained titanium, Appl. Phys. Lett. 79, 611 (2001).
  19. Q. Wei, D. Jia, K. T. Ramesh, and E. Ma, Evolution and microstructure of shear bands in nanostructured Fe, Appl. Phys. Lett. 81, 1240 (2002).
  20. D. Jia, K. T. Ramesh, and E. Ma, Effects of nanocrystalline and ultrafine grain sizes on constitutive behavior and shear bands in iron, Acta Mater. 51, 3495 (2003).
  21. M. A. Meyers, A. Mishra, and D. J. Benson, Mechanical properties of nanocrystalline materials, Prog. Mater. Sci. 51, 427 (2006).
  22. K. T. Ramesh, Nanomaterials—Mechanics and Mechanisms. Nanomaterials—Mechanics and Mechanisms (Springer, New York, 2009).
  23. S. Osovski, Y. Nahmany, D. Rittel, P. Landau, and A. Venkert, On the dynamic character of localized failure, Scr. Mater. 67, 693 (2012).
  24. S. Chen, D. Rittel, and D. Mordehai, A percolative deformation process between nanograins promotes dynamic shear localization, Mater. Res. Lett. 3, 76 (2015).
  25. P. S. Follansbee and G. T. Gray, The response of single crystal and polycrystal nickel to quasistatic and shock deformation, Int. J. Plast. 7, 651 (1991).
  26. G. T. Gray III, in High-Pressure Shock Compression of Solids (Springer, New York, 1993), p. 187.
  27. A. Rohatgi, K. S. Vecchio, and I. G. T. Gray, A metallographic and quantitative analysis of the influence of stacking fault energy on shock-hardening in Cu and Cu-Al alloys, Acta Mater. 49, 427 (2001).
  28. A. Dorogoy, D. Rittel, and A. Godinger, Modification of the shear-compression specimen for large strain testing, Exp. Mech. 55, 1627 (2015).
  29. H. Kolsky, An investigation of the mechanical properties of materials at very high rates of loading, Proc. Phys. Soc. London Sect. B 62, 676 (1949).
  30. P. Landau, A. Venkert, and D. Rittel, Microstructural aspects of adiabatic shear failure in annealed Ti6Al4V, Metall. Mater. Trans. A 41, 389 (2010).
  31. O. Bouaziz, Y. Estrin, Y. Bréchet, and J. D. Embury, Critical grain size for dislocation storage and consequences for strain hardening of nanocrystalline materials, Scr. Mater. 63, 477 (2010).
  32. S. P. Joshi and K. T. Ramesh, Rotational diffusion and grain size dependent shear instability in nanostructured materials, Acta Mater. 56, 282 (2008).
  33. Q. Wei, L. Kecskes, T. Jiao, K. T. Hartwig, K. T. Ramesh, and E. Ma Adiabatic shear banding in ultrafine-grained Fe processed by severe plastic deformation, Acta Mater. 52, 1859 (2004).
  34. S. Osovski, D. Rittel, and A. Venkert, The respective influence of microstructural and thermal softening on adiabatic shear localization, Mech. Mater. 56, 11 (2013).

Outline

Information

Phys. Rev. Applied 7, 044012– Published 19 April, 2017
  • Received 12 November 2016

© 2017 American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation