Materials Transactions Online

Materials Transactions, Vol.44 No.6 (2003) pp.1198-1203
© 2003 The Japan Institute of Metals

Capacity for Deformation and the Evaluation of Flow Stress of Hot Extruded Mg-8Al-xRE Alloys at Elevated Temperatures

Wan-Gye Yang* and Chun-Hao Koo**

Department of Materials Science and Engineering, National Taiwan University, Taipei, 106 Taiwan, R.O. China

This paper investigated the optimal deformation temperature Tc, and the optimal Zener-Hollomon parameter Zc, of both as-extruded Mg-8Al and Mg-8Al-2RE alloys, to examine the capacity of these alloys for deformation. Additionally, an equation that involves the Zener-Hollomon parameter Z was derived to evaluate the flow stress of these magnesium alloys at various temperatures and strain rates and was validated using a statistical method. These alloys were prepared by melting and casting in a vacuum induction furnace, and extruded at 633 K with a reduction ratio of 90:1. Tensile tests were performed at 473 to 723 K and at strain rates ranging from 8.3× 10-4 to 8.3× 10-1 s-1. The implications of the experimental data were discussed in detail.

(Received February 24, 2003; Accepted May 6, 2003)

Keywords: magnesium alloys, rare-earth element, extrusion, mechanical properties, hot working, Zener-Hollomon parameter

*Graduate Student, National Taiwan University.
**Corresponding author: E-mail:

PDF(Free)PDF (Free) Table of ContentsTable of Contents


  1. W. G. Yang and C. H. Koo: Mater. Trans. 44 (2003) 1029-1035[JIM].
  2. H. Watanabe, T. Mukai, M. Kohzu, S. Tanabe and K. Higashi: Acta Mater. 47 (1999) 3753-3758.
  3. H. Watanabe, T. Mukai, M. Mabuchi and K. Higashi: Acta Mater. 49 (2001) 2027-2037.
  4. W. J. Kim, S. W. Chung, C. S. Chung and D. Kum: Acta Mater. 49 (2001) 3337-3345.
  5. X. Wu and Y. Liu: Scr. Mater. 46 (2002) 269-274.
  6. H. Takuda, H. Fujimoto and N. Hatta: J. Mater. Process. Technol. 80-81 (1998) 513-516.
  7. C. J. Lin: Superplastic forming and application of the metals, (Aviation industry publishing house, Beijing, 1990) pp. 10-11.
  8. M. A. Meyers and K. K. Chawla: Mechanical Behavior of Materials, (Prentice-Hall International, New Jersey, 1999) p. 270.
  9. G. E. Dieter: Mechanical Metallurgy, (McGraw-Hill Book Co., London, 1988) p. 188.
  10. Z. Jeffries: Trans. AIME 60 (1919) 474-576.
  11. C. Zener and H. Hollomon: J. Appl. Phys. 15 (1943) 22-32.
  12. H. J. Forst and M. F. Ashby: Deformation Mechanism Maps, (Pergamon Press, Oxford, 1982) p. 44.
  13. O. D. Sherby and J. Wadsworth: Prog. Mater. Sci. 33 (1989) 169-221.
  14. T. G. Langdon: Metall. Trans. A 13A (1982) 689-701.
  15. J. W. Edington: Metall. Trans. A 13A (1982) 703-715.
  16. R. Z. Valiev and O. A. Kaibyshev: Acta Mater. 31 (1983) 2121-2128.
  17. G. E. Dieter: Mechanical Metallurgy, (McGraw-Hill Book Co., London, 1988) p. 307.
  18. R. J. Larsen and M. L. Marx: An Introduction to Mathematical Statistics and Its Applications, (Prentice Hall, New York, 2001) p. 558.


© 2002 The Japan Institute of Metals
Comments to us :