Forming Limit of AZ31 Magnesium Alloy Sheet under Non-Proportional Deformation at Elevated Temperature

Abstract:

In the present work, FLDs of AZ31 magnesium alloy sheet for non-proportional strain paths were investigated by performing two-step stretch forming experiments at various forming speeds (3, 30 and 300 mm.min^-1) at elevated temperatures of 150, 200 and 250°C. The forming limit strains, both for proportional and non-proportional deformations, increased with temperature rise and with decreasing forming speed. A FLC after a uniaxial pre-strain lies outside of the proportional FLC for a given condition of temperature and forming speed, whereas a biaxially pre-strained FLC lies inside of the proportional FLC. It was found that the accumulated effective plastic strain and the direction of plastic strain increment at the final stage of forming are two major factors that influence the forming limits for non-proportional deformations.

• Periodical: Key Engineering Materials (Volumes 535-536)
• Pages: 292-295
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.535-536.292
• Online since: January 2013
• Authors: Takashi Katahira, Tetsuo Naka, Masahide Kohzu, Fusahito Yoshida
• Keywords: AZ31 Magnesium Alloy Sheets, Non-Proportional FLD, Warm Forming

References

[1] Y. Kojima, Project of platform science and technology for advanced magnesium alloys, Mater. Trans., 42 (2001), p.1154–1159

DOI: 10.2320/matertrans.42.1154

[2] S. Schumann, H. Friedrich, Current and future use of magnesium in the automobile industry, Mater. Sci. Forum, 419-420(2003), pp.51-56

DOI: 10.4028/www.scientific.net/msf.419-422.51

[3] H. Friedrich, S. Schumann, Research for a "new age of magnesium" in the automotive industry, J. Mater. Process. Technol. 117(2011), pp.276-281

[4] E. Doege, K. Droder, Sheet metal forming of magnesium wrought alloys-formability and process technology, J. Mater Process. Technol. 115(2001), pp.14-19.

DOI: 10.1016/s0924-0136(01)00760-9

[5] H. Somekawa, M. Kohzu, S. Tanabe, H. Higashi, The press formability in magnesium alloy AZ31. Mater. Sci. Forum. 350-351 (2000), pp.177-182

DOI: 10.4028/www.scientific.net/msf.350-351.177

[6] M. Kohzu, F. Yoshida, H. Somekawa, M. Yoshikawa, S. Tanabe, Deep-drawing of magnesium alloy AZ31. Mater. Trans. 42(2001), pp.648-653

DOI: 10.2320/matertrans.42.1273

[7] T. Naka, T. G. Torikai, R. Hino, F. Yoshida, The effects of temperature and forming speed on forming limit diagram for type 5083 aluminum-magnesium alloy sheet. J. Mater. Process. Technol. 113(2001), pp.276-281

DOI: 10.1016/s0924-0136(01)00650-1

[8] T. Naka, T., Nakayama, T., Uemori, T., Hino, R., Yoshida, F., Kohzu, M., Higashi, K.: FLD of AZ31 Sheet under Warm Stretching and Its Prediction, International Journal of Modern Physics B, 22-31/32 (2008), pp.6010-6015

DOI: 10.1142/s0217979208051509

[9] A. Graf, W. Hosford, Effect of changing strain path on forming limit of Al2008-T8, Metallugical Trans., 24A (1993), pp.65-75

[10] R. Hino, A. Hirahara, Y. Fujii, F. Yoshida, Forming limt of high strength steel sheets under non-proportional deformation, Proceedings of the 10th Int. Conf. Technology of Plasticity (ICTP2011), pp.912-916

DOI: 10.4028/www.scientific.net/amr.939.260