Threshold Stress for Super Plastic Flow in Spatially Extended Crystalline Systems

Abstract:

Article Preview

In general, the mechanical behavior of superplastic spatially extended crystalline systems (SP-SECS) is characterized by a sigmoidal relationship between the applied stress and the steady state strain rate. The sigmoidal curve is defined by three regions: low stress - region I, intermediate stress or superplastic - region II and high stress - region III. The region I is known as the region where the threshold stress exists, but there are controversies on their existence. In this way, some experimental results reported in the past are analyzed. Earlier investigations have reported the apparent activation energy for creep in SP-SECS as a function of the applied stress, where it is exhibited a marked dependence of impurities or precipitates concentration. In addition, recent experimental evidences have revealed that the unified interpretation of creep, plasticity and superplasticity is the deductive rule [1]. In order to describe the interaction between precipitates at grain boundaries and dislocations during deformation processes a phenomenological expression for the threshold stress at the Grain Boundary in SP-SECS is described in this work.

Info:

Periodical:

Materials Science Forum (Volumes 475-479)

Main Theme:

Edited by:

Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie

Pages:

3013-3016

Citation:

J. D. Muñoz-Andrade, "Threshold Stress for Super Plastic Flow in Spatially Extended Crystalline Systems", Materials Science Forum, Vols. 475-479, pp. 3013-3016, 2005

Online since:

January 2005

Export:

Price:

$38.00

[1] J. D. Muñoz-Andrade: Physical Theory of Superplastic Flow in Spatially Extended Crystalline Systems, ICSAM 2003, 8 th International Conference on Superplasticity in Advanced Materials, July 28 th - 30 th, 2003, St. Catherie´s College, Oxford, UK., Mater. Sci. Forum Vols. 447-448 (2004).

DOI: https://doi.org/10.4028/www.scientific.net/msf.447-448.85

[2] Juan D. Muñoz-Andrade: Activation Energy for Irreversible Deformation Processes in Spatially Extended Crystalline Systems, Materials Processing and Design: Modeling, Simulation and Applications, NUMIFORM 2004, edited by S. Ghosh, J. C. Castro, and J. L. Lee, American Institute of Physics (2004).

DOI: https://doi.org/10.1063/1.1766758

[3] J. D. Muñoz-Andrade: Cavitation During Superplastic Flow in Spatially Extended Crystalline Systems, EURO-SPF 2004, European Conference on Super Plastic Forming, July 7 th - 9 th- 2004, Ecole Des Mines d´Álbi Carmaux, France.

[4] G. E. Dieter: in Mechanical Metallurgy, , McGraw-Hill International Editions, USA, (1996) p.181.

[5] Prabir K. Chaudhury and Farghalli A. Mohamed, Acta metal. Vol. 36, No. 4 (1988) p.10991110.

[6] J.A. Montemayor-Aldrete, J. D. Muñoz-Andrade and A. Mendoza-Allende, Rev. Mex. Fís. 48(3) (2002) 210-214.

[7] J. D. Muñoz-Andrade: The Universe as a Crystal, , Abstract presented at Symposium Current Topics in Physics in Honor of Sir Roger Elliot, Instituto de Física, Universidad Nacional Autónoma de México, UNAM, June 17 th-19 th , (2003).