Skip to main content

Dislocation Activity in AZ31B Magnesium Deformed at Moderately Elevated Temperatures via EBSD

  • Chapter
Magnesium Technology 2014
  • 1928 Accesses

Abstract

Activation of <c+a> type slip in wrought magnesium has typically been associated with forming temperatures of 200°C or higher, while contraction twinning has been observed to be more prevalent at lower temperatures. A recent investigation showed that when AZ31B sheets with strong basal texture were formed in biaxial or plane strain tension at room temperature, contraction twins were observed in banded structures. These banded structures disappeared at moderate forming temperatures of 75°C and 125°C. The hypothesis is that <c+a> type slip was sufficiently activated at the moderate forming temperatures that thinning of the sheet was accommodated less by twinning and more by slip. This paper uses mesoscale electron backscatter diffraction continuum dislocation microscopy in an SEM to determine <c+a> type geometrically necessary dislocation density. Preliminary results suggest that the relative amount of <c+a> geometrically necessary dislocations is unrelated to the onset of twinning.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 189.00
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 169.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Agnew, S.R., M.H. Yoo, and C.N. Tomé, Application of texture simulation to understanding mechanical behavior of Mg and solid solution alloys containing Li or Y. Acta Materialia, 2001. 49(20): p. 4277–4289.

    Article  Google Scholar 

  2. Agnew, S.R., J.A. Horton, and M.H. Yoo, Transmission Electron Microscopy of <c + a> Dislocations in Mg and Alpha-Solid Solutions of Mg-Li Alloys. Metallurgical and Materials Transactions A, 2002. 33A: p. 851–858.

    Article  Google Scholar 

  3. Koike, J., et al., The activity of non-basal slip systems and dynamic recovery at room temperature in finegrained AZ31b magnesium alloys. Acta Mater, 2003. 51: p. 2055–65.

    Article  Google Scholar 

  4. Koike, J., Enhanced deformation mechanisms by anisotropic plasticity in polycrystalline magnesium alloys at room temperature. Metall. Mater. Trans.A, 2005. 36: p. 1689–96.

    Article  Google Scholar 

  5. Wu, L. Twinning-detwinning behavior during the strain-controlled low-cycle fatigue testing of a wrought magnesium alloy, ZK60A. Acta Materialia, 2008. 56(4): p. 688–695.

    Article  Google Scholar 

  6. Sandlöbes, S., On the role of non-basal deformation mechanisms for the ductility of Mg and Mg-Y alloys. Acta Materialia, 2011. 59(2): p. 429–439.

    Article  Google Scholar 

  7. Jiang L, J.J., Mishra RK, Luo AA, Sachdev AK, Godet S., Twinning and texture development in two Mg alloys subjected to loading along three different strain paths. Acta Mater., 2007(55): p. 3899–3910.

    Google Scholar 

  8. Martin, É., Variant selection during secondary twinning in Mg-3%Al. Acta Materialia, 2010. 58(11): p. 3970–3983.

    Article  Google Scholar 

  9. Park, S.H., S.-G. Hong, and C.S. Lee, Activation mode dependent {10–12} twinning characteristics in a polycrystalline magnesium alloy. Scripta Materialia, 2010. 62(4): p. 202–205.

    Article  Google Scholar 

  10. Hong, S.-G., S.H. Park, and CS. Lee, Role of {10–12} twinning characteristics in the deformation behavior of a polycrystalline magnesium alloy. Acta Materialia, 2010. 58(18): p. 5873–5885.

    Article  Google Scholar 

  11. Chino, Y., K. Kimura, and M. Mabuchi, Deformation characteristics at room temperature under biaxial tensile stress in textured AZ31 Mg alloy sheets. Acta Materialia, 2009. 57(5): p. 1476–1485.

    Article  Google Scholar 

  12. Hutchinson, W.B. and M.R. Barnett, Effective values of critical resolved shear stress for slip in polycrystalline magnesium and other hcp metals. Scripta Materialia, 2010. 63(7): p. 737–740.

    Article  Google Scholar 

  13. Agnew, S.R., et al., Study of slip mechanisms in a magnesium alloy by neutron diffraction and modeling. Scripta Materialia, 2003. 48: p. 1003–1008.

    Article  Google Scholar 

  14. Brown, D., et al., Internal strain and texture evolution during deformation twinning in magnesium. Materials Science and Engineering: A, 2005. 399(1–2): p. 1–12.

    Article  Google Scholar 

  15. Barnett, M., Twinning and the ductility of magnesium alloys Part II Contraction twins. Mater. Sci. Eng A, 2007. 464: p. 8–16.

    Article  Google Scholar 

  16. Chapuis, A. and J.H. Driver, Temperature dependency of slip and twinning in plane strain compressed magnesium single crystals. Acta Materialia, 2011. 59(5): p. 1986–1994.

    Article  Google Scholar 

  17. Chapuis, A. and J. Driver, A fundamental study of the high temperature deformation mechanisms of magnesium. Journal of Physics A: Mathematical and General, 2012: p. 420.

    Google Scholar 

  18. Ono, N., R. Nowak, and S. Miura, Effect of deformation temperature on Hall-Petch relationship registered for polycrystalline magnesium. Materials Letters, 2003. 58(1–2): p. 39–43.

    Google Scholar 

  19. Barnett, M.R., Twinning and the ductility of magnesium alloys: Part I: ‘Tension’ twins. Materials Science and Engineering: A, 2007. 464(1–2): p. 1–7.

    Article  Google Scholar 

  20. Li, H., et al., Determination of Active Slip/Twinning Modes in AZ31 Mg Alloy Near Room Temperature. JMEPEG, 2007. 16(321–326).

    Google Scholar 

  21. Chen, F.-K. and T.-B. Huang, Formability of stamping magnesium-alloy AZ31 sheets. Journal of Materials Processing Technology, 2003.142(3): p. 643–647.

    Article  Google Scholar 

  22. Jager, A., Tensile properties of hot rolled AZ31 Mg alloy sheets at elevated temperatures. Journal of Alloys and Compounds, 2004. 378(1–2): p. 184–187.

    Article  Google Scholar 

  23. Lee, Y., et al., Experimental and analytical studies for forming limit of AZ31 alloy on warm sheet metal forming. Journal of Materials Processing Technology, 2007. 187–188: p. 103–107.

    Article  Google Scholar 

  24. Miles, M.P., et al., Metall. Trans. A, 1993. 24A: p. 1143–1151.

    Article  Google Scholar 

  25. Gardner, C.J., et al., EBSD-based continuum dislocation microscopy. International Journal of Plasticity, 2010. 26: p. 1234–1247.

    Article  Google Scholar 

  26. Ruggles, T.J. and D.T. Fullwood, Estimations of bulk geometrically necessary dislocation density using high resolution EBSD. Ultramicroscopy, 2013. 133: p. 8–15.

    Article  Google Scholar 

  27. Wilkinson, A.J., G. Meaden, and D.J. Dingley, High resolution mapping of strains and rotations using electron back scatter diffraction. Materials Science and Technology, 2006. 22(11): p. 1–11.

    Article  Google Scholar 

  28. Wilkinson, A.J., G. Meaden, and D.J. Dingley, High-resolution elastic strain measurement from electron bockscotter diffraction patterns: New levels of sensitivity. Ultramicroscopy, 2006.106: p. 307–313.

    Article  Google Scholar 

  29. Nye, J.F., Some geometrical relations in dislocated crystals. Acta Metallurgica, 1953. 1: p. 153–162.

    Article  Google Scholar 

  30. Kroner, E., Continuum theory of dislocations and self-stresses. Ergebnisse der Angewandten Mathematik, 1958. 5: p. 1327–1347.

    Google Scholar 

  31. Pantleon, W., Resolving the goemetrically necessary dislocation content by conventional electron backscattering diffraction. Scripta Materialia, 2008. 58: p. 994–997.

    Article  Google Scholar 

  32. Sun, S., B.L. Adams, and W.E. King, Observations of lattice curvature near the interface of a deformed aluminium bicrystal. Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties, 2000. 80(1): p. 9–25.

    Article  Google Scholar 

  33. Field, D.P., Improving the spatial resolution of EBSD. Microsc Microanal, 2005. 11: p. 52–53.

    Article  Google Scholar 

  34. El-Dasher, B.S., B.L. Adams, and A.D. Rollett, Viewpoint: Experimental recovery of geometrically necessary dislocation density in polycrystals. Scripta Materialia, 2003. 48(2): p. 141–145.

    Article  Google Scholar 

  35. Littlewood, P.D., T.B. Britton, and A.J. Wilkinson, Geometrically necessary dislocation density distribution in Ti-6AI-4V deformed in tension. Acta Materialia, 2011. 59: p. 6489–6500.

    Article  Google Scholar 

  36. Kysar, J.W., et al., Experimental lower bounds on geometrically necessary dislocation density. International Journal of Plasticity, 2010. 26: p. 1097–1123.

    Article  Google Scholar 

  37. Kysar, J.W., et al., High strain gradient plasticity associated with wedge indentation into face-centered cubic single crystals: Geometrically necessary dislocation densities. Journal of the Mechanics and Physics of Solids, 2007. 55: p. 1554–1573.

    Article  Google Scholar 

  38. Khosravani, A., et al., Twinning in magnesium alloy AZ31B under different strain paths at moderately elevated temperatures. International Journal of Plasticity, 2013. 45: p. 160–173.

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2014 TMS (The Minerals, Metals & Materials Society)

About this chapter

Cite this chapter

Ruggles, T., Khosravani, A., Fullwood, D., Miles, M.P. (2014). Dislocation Activity in AZ31B Magnesium Deformed at Moderately Elevated Temperatures via EBSD. In: Alderman, M., Manuel, M.V., Hort, N., Neelameggham, N.R. (eds) Magnesium Technology 2014. Springer, Cham. https://doi.org/10.1007/978-3-319-48231-6_27

Download citation

Publish with us

Policies and ethics