5. Conclusions
The formability of AZ31B magnesium alloy sheets was investigated in the present study by the tensile test, the deep drawing test and the cold stamping test of cell phone housing. The research results indicate that, compared with the as received sheets, the RUB processed sheets exhibit a lower yield strength, a lower yield ratio, a larger fracture elongation, a smaller Lankford value (r-value), a larger strain hardening exponent (n-value) and a superior stretch formability. The LDR of the RUB processed sheets can reach 1.5 at room temperature. It is verified that the magnesium alloy sheet with a tilted texture obtained by RUB process has favorable formability at room temperature. It was also confirmed that cell phone housing could be produced successfully in crank press using the RUB processed AZ31B sheet by the stamping process.
Acknowledgements
Sincere thanks are given to the National Natural Science Foundation of China under Grant no. 50504019, Natural Science
Foundation of CQ CSCT under Grant no. 2008BB4040 and Scientific and Technological Project of CQ CSCT under Grant no. 2008AA4028 for their supports.
References
Agnew, S.R., Duygulu, O., 2005. Plastic anisotropy and the role of non-basal slip in magnesium alloy AZ31B. Int. J. Plasticity 21, 1161–1193.
Agnew, S.R., Senn, J.W., Horton, J.A., 2006. Mg Sheet metal forming: lessons learned from deep drawing Li and Y solid-solution alloys. JOM 58 (5), 62–69.
ASM Committee on Fabrication of Magnesium, 1969. Metals Handbook, vol. 4(8), pp. 424–431.
Chen, F.K., Huang, T.B., 2003. Formability of stamping magnesium-alloy AZ31 sheets. J. Mater. Proc. Technol. 142, 643–647.
Cheng, Y.Q., Chen, Z.H., Xia, W.J., 2007. Drawability of AZ31 magnesium alloy sheet produced by equal channel angular rolling at room temperature. Mater. Charact.58, 617–622.
Chino, Y., Lee, J.S., Sassa, K., Kamiya, A., Mabuchi, M., 2006. Press formability of a rolled AZ31 Mg alloy sheet with controlled texture. Mater. Lett. 60, 173–176.
Doege, E., Droder, K., 2001. Sheet metal forming of magnesium wrought alloys – formability and process technology. J. Mater. Proc. Technol. 115, 14–19.
Huang, G.S., Li, H.C., Song, B., Zhang, L., 2010. Tensile properties and microstructure of AZ31B magnesium alloy sheet processed by repeated unidirectional bending. Trans. Nonferrous Met. Soc. 20 (1), 28–33.
Huang, G.S., Xu, W., Huang, G.J., Li, H.C., Song, B., 2009. Textural evolution of AZ31B magnesium alloy sheets undergoing repeated unidirectional bending at room temperature. Mater. Sci. Technol. 25, 365–369.
Huang, X.S., Suzuki, K., Watazu, A., Shigematsu, I., Saito, N., 2009. Improvement of formability of Mg–Al–Zn alloy sheet at low temperatures using differential speed rolling. J. Alloys Compd. 470, 263–268.
Iwanaga, K., Tashiro, H., Okamoto, H., Shimizu, K., 2004. Improvement of formability from room temperature to warm temperature in AZ-31 magnesium alloy. J. Mater. Proc. Technol. 155, 1313–1316.
Kim, W.J., Hong, S.I., Kim, Y.S., Min, S.H., Jeong, H.T., Lee, J.D., 2003. Texture development and its effect on mechanical properties of an AZ61 Mg alloy fabricated by equal channel angular pressing. Acta Mater. 51, 3293–3307.
Koike, J., Kobayashia, T., Mukaib, T., Watanabeb, H., Suzukia, M., Maruyamaa, K., Higashic, K., 2003. The activity of non-basal slip systems and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys. Acta Mater. 44,2065–4455.
Lee, D.N., 1984. Relation between limiting drawing ratio and plastic strain ratio. J. Mater. Sci. Lett. 3 (8), 677–680.
Mori, K., Tsuji, H., 2007. Cold deep drawing of commercial magnesium alloy sheets. CIRP Ann. 56, 285–288.
Mori, K., Nishijima, S., Tan, C.J., 2009. Two-stage cold stamping of magnesium alloy cups having small corner radius. Int. J. Mach. Tools Manuf. 49 (10), 767–772.