Plastic deformation behavior of ZK60 magnesium alloy with addition of neodymium

Abstract

The hot deformation simulation of a ZK60 magnesium alloy at different temperatures from 373 to 673 K and different strain rates of 0.1, 0.01 and 0.002 s⁻¹ was studied by using the Gleebe-1500 simulator. The plastic deformation behavior was measured and the deformation activation energy was calculated. The microstructures of ZK60 magnesium alloy with an addition of neodymium during the deformation process were observed by using Polyvar-MET optical microscope and Tecnai G² 20 TEM. The results show that the working hardening, the dynamic recovery and the dynamic recrystallization occur during the plastic deformation process at different temperatures and strain rates. The dynamic recrystallization starts when the temperature is over 473 K and the DRX grain size after hot deformation is only 5–10 μm. So the refined grains improve both the tensile strength and the elongation of alloys at room temperature. Neodymium is added into the alloy and a precipitate phase Mg₁₂Nd that impedes the movement of dislocations is formed, which benefits to increasing mechanical properties of ZK60 magnesium alloy.

Keywords

ZK60 magnesium alloy / rare earth / plastic deformation behavior / dynamic recrystallization

References

[1] ASM International.Magnesium and magnesium alloy [M], 1999, Ohio, Metal Park: 1-130

[2] LiW.-xian.Magnesium and magnesium alloy [M], 2005, Changsha, Central South University of Technology Press: 338-380

[3] CahnR. W.Microstructures and properties of nonferrous alloys [M], 1999, Beijing, Science Press: 460-485

[4] BussibaA., ArtzyB. A., ShtechmanA.. Grain refinement of AZ31 and ZK60 Mg alloys—Towards superplasticity studies [J]. Mater Sci Eng A, 2001, A302: 56-62

[5] YuK., LiW.-x., WangR.-chu.. Research, development and application of wrought magnesium alloys [J]. The Chinese Journal of Nonferrous Metals, 2003, 13(2): 277-282

[6] LuoZ. P., SongD. Y., ZhangS. Q.. Strengthening effects of rare-earths on wrought Mg-Zn-Zr-RE alloys [J]. Journal of Alloys and Compounds, 1995, 230(2): 109-114

[7] WeiL. Y., DunlopG. L., WestengenH.. Age hardening and precipitation in a cast magnesium rare-earth alloy [J]. Journal of Materials Science, 1996, 31(2): 387-397

[8] NieJ. F., MuddleB. C.. Characterization of strengthening precipitate phases in a Mg-Y-Nd alloy [J]. Acta Materialia, 2000, 48(8): 1691-1703

[9] NieJ. F.. Effects of precipitate shape and orientation on dispersion strengthening in magnesium alloys [J]. Scripta Materialia, 2003, 48(8): 1009-1015

[10] YuK., LiW.-x., WangR.-chu.. Mechanical properties and microstructure of as-cast and extruded Mg-(Ce,Nd)-Zn-Zr alloys [J]. Journal of Central South University of Technology, 2005, 12(5): 499-502

[11] KojimaY.. Progressive steps in the platform science and technology for advanced magnesium alloys [J]. Mater Sci Forum, 2003, 419/422: 3-20

[12] ParkW. J., ParkH., KimD. H.. Structure and decomposition behavior of rapid solidified Mg-Nd-X alloys [J]. Mater Sci Eng A, 1994, A179/180: 637-640

[13] JiZ.-sheng.. Research process and new technology of magnesium alloy in Japan [J]. The Chinese Journal of Nonferrous Metals, 2004, 14(12): 1977-1984

[14] KHOSRHOSHAHI R A, PILKINGTON R, LORIMER G W. The microstructure and creep of as-cast and extruded WE54 alloy [C]// Proceeding of the Third International Magnesium Conference. Manchester, 1996: 261–256.

[15] LuoA.. Magnesium castings for automotive applications [J]. JOM, 1995, 47(1): 28-31