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Electropulsing-induced phase transformations in a Zn–Al-based alloy

Published online by Cambridge University Press:  31 January 2011

Yaohua Zhu*
Affiliation:
Department of Industrial and Systems Engineering, Hong Kong Polytechnic University, Hong Kong 852, China
Wing B. Lee
Affiliation:
Department of Industrial and Systems Engineering, Hong Kong Polytechnic University, Hong Kong 852, China
Xingming Liu
Affiliation:
Hefei National Laboratory for Physical Science at Microscales, University of Science and Technology of China, Hefei, China
Guoyi Tang
Affiliation:
Graduate School at ShenZhen, Tsinghua University, Tsinghua, China
*
a) Address all correspondence to this author. e-mail: mfyhzhu@inet.polyu.edu.hk
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Abstract

Microstructural changes and phase transformations of an electropulsing-treated (EPT) ZA22 alloy wire were studied using scanning electron microscopy and transmission electron-microscopy techniques. Two stages of phase transformation were detected in the EPT alloy: (i) quenching from the as furnace-cooled (FC) state to the final stable state and (ii) up-quenching from the final stable state back to the as FC state through two reverse phase transformations: T′ + η → α + ε and η′T + ε + α → η′FC. Electropulsing accelerated phase transformation tremendously. It was at least 1200 times faster than the aging process. The mechanism of the electropulsing-induced phase transformations is discussed from the point of view of Gibbs free energy and electropulsing kinetics.

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Articles
Copyright
Copyright © Materials Research Society 2009

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References

1Troitskii, O.A.: Electromechnical effect in metals. Zh. Eksp. Teor. Fiz. 10, 18 (1969).Google Scholar
2Sprecher, A.F., Mamnna, S.L., and Conrad, H.: On the mechanisms for the electroplastic effect in metals. Acta Metall. 34, 1145 (1986).CrossRefGoogle Scholar
3Yang, D. and Conrade, H.: Exploratory study into the effects of an electric field and high current density electropulsing on the plastic deformation of TiAl. Intermetallics 9, 943 (2001).CrossRefGoogle Scholar
4Okazaki, K., Kagawa, K., and Conrad, H.: An evaluation of the contribution of skin, pinch and heating effects to the electroplas-tic effects in titanium. Mater. Sci. Eng., A 45, 109 (1980).CrossRefGoogle Scholar
5Lloyd, J.R.: Electromigration in integrated circuit conductors. J. Phys. D: Appl. Phys. 32, R109 (1999).CrossRefGoogle Scholar
6Gupta, R.P., Serruys, Y., Brebec, G., and Adda, Y.: Calculation of the effective valence for electromigration in niobium. Phys. Rev. B 2, 669 (1983).Google Scholar
7Xu, Z.H., Tang, G.Y., Ding, F., Tian, S.Q., and Tian, H.Y.: The effect of multiple pulse treatment on the recrystallization behavior of M3Al-1Zn alloy strip. Appl. Phys. A 88, 429 (2007).CrossRefGoogle Scholar
8Xiao, S.H., Guo, J.D., Wu, S.D., He, G.H., and Li, S.X.: Recrystallization in fatigue copper single crystals under electropulsing. Scr. Mater. 46, 1 (2002).CrossRefGoogle Scholar
9Jiang, Y.B., Tang, G.Y., Shek, C.H., Zhu, Y.H., Guan, L., Wang, S.N., and Xu, Z.H.: The effect of electropulsing treatment on the solid solution behavior of aged AZ61 alloy strip. J. Mater. Res. 23, 2685 (2008).CrossRefGoogle Scholar
10Onodera, Y. and Hirano, K.I.: The effect of direct electric current on precipitation in a bulk Al-4% Cu alloy. J. Mater. Sci. 11, 809 (1976).CrossRefGoogle Scholar
11Conrad, H.: Effects of electric current on solid-state phase transformations in metals. Mater. Sci. Eng., A 287, 227 (2000).CrossRefGoogle Scholar
12Zhang, W., Sui, M.L., Zhou, Y.Z., and Li, D.X.: Evolution of microstructures in materials induced by electropulsing. Micron 34, 189 (2003).CrossRefGoogle ScholarPubMed
13Zhou, Y.Z., Guo, J.D., Zhang, W., and He, G.H.: Influence of elec-tropulsing on nucleation during phase transformation. J. Mater. Res. 17, 3012 (2002).CrossRefGoogle Scholar
14Zhu, Y.H., To, S., Lee, W.B., Liu, X.M., Jiang, Y.B., and Tang, G.Y.: Effects of dynamic electropulsing on microstructure and elongation of a Zn-Al alloy. Mater. Sci. Eng., A 501, 125 (2009).CrossRefGoogle Scholar
15To, S., Zhu, Y.H., Lee, W.B., Liu, X.M., Jiang, Y.B., and Tang, G.Y.: Effects of current density on electropulsing induced phase transformation in a Zn-Al based alloy. Appl. Phys. A (in press).Google Scholar
16Conrad, H. and Sprecher, A.F.: Dislocation in Solids (Elsevier, Amsterdam, The Netherlands, 1989).Google Scholar
17Gumbsch, P. and Gao, H.J.: Dislocations faster than the speed of sound. Science 283, 965 (1998).CrossRefGoogle Scholar
18Xiao, L. and Gu, H.C.: Dislocation structures in zirconium and ziecaloy-4 fatigued at different temperatures. Metall. Mater. Trans. A 28, 1021 (1997).CrossRefGoogle Scholar
19Conrad, H., White, J., Cao, W.D., Lu, X.P., and Sprecher, A.F.: Effect of electric current pulses on fatigue characteristics of polycrystalline copper. Mater. Sci. Eng., A 145, 1 (1991).CrossRefGoogle Scholar
20Zhou, Y.Z., Qin, S.R., Xiao, S.H., He, G.H., and Zhou, B.L.: Reversing effect of electropulsing on damage of 1045 steel. J. Mater. Res. 15, 1056 (2000).CrossRefGoogle Scholar
21Xu, Z.S., Lai, Z.H., and Chen, Y.X.: Effect of electric current on the recrystallization behavior of cold worked a–Ti. Scr. Metall. 22, 187 (1988).CrossRefGoogle Scholar
22Ding, F., Tang, G.Y., Xu, Z.H., and Tian, S.Q.: A new method for improving strength and plasticity of steel wire. J. Mar. Sci. Technol. 23, 160 (2007).Google Scholar
23Qin, R.S. and Zhou, B.L.: Effect of electric current pulses on grain size in castings. Int. J. Non Equilibr. Process 11, 77 (1998).Google Scholar
24Zhu, Y.H. and Murphy, S.: General rule of decomposition reaction in supersaturated Zn-Al based alloy. Chin. J. Metal Sci. Technol. 2, 1 (1986).Google Scholar
25Zhu, Y.H.: General rule of phase decomposition in Zn-Al based alloys. II: On effect of external stress on phase transformation. Mater. Trans., JIM 45, 3083 (2004).CrossRefGoogle Scholar
26Zhu, Y.H.: Microstructural changes in welded Zn-Al alloy. J. Mater. Res. 11, 593 (1996).CrossRefGoogle Scholar
27Zhu, Y.H., Man, H.C., Dorantes-Rosales, H.C., and Lee, W.B.: Ageing characteristics of furnace cooled eutectoid Zn-Al based alloy. J. Mater. Sci. 38, 2925 (2003).CrossRefGoogle Scholar
28Zhu, Y.H. and Lee, W.B.: Tensile deformation and phase transformation of furnace cooled Zn-Al alloy. Mater. Sci. Eng., A 293, 95 (2000).CrossRefGoogle Scholar
29Zhu, Y.H. and Orozco, E.: Effects of tensile stress on microstruc-tural change of eutectoid Zn-Al alloy. Metall. Mater. Trans. A 26, 2611 (1995).CrossRefGoogle Scholar
30Zhu, Y.H. and Torres, J.: Tensile deformation in extruded eutec-toid Zn-Al based alloy. Zeit Metall. 88, 392 (1997).Google Scholar
31Zhu, Y.H., Lee, W.B., and To, S.: Tensile stress induced phase transformation of cast alloy ZnAl7Cu3. Mater. Res. Bull. 38, 1851 (2003).CrossRefGoogle Scholar
32Zhu, Y.H., Lee, W.B., Chung, C.Y., and To, S.: On nanophase stability in eutectoid Zn-Al based alloy films. Appl. Surf. Sci. 236, 106 (2004).CrossRefGoogle Scholar