摘要

As a very important design principle, the dynamic properties of materials attracted extensive attention in resent years and a bunch of works have been done concerning with the materials deformation behaviors under high strain rates. However, the dynamic behaviors of magnesium alloys are not through understood, especially the rare earth based magnesium alloys. In order to investigate the dynamic and anisotropic behavior under high strain rates deformation of as-extruded Mg-3Zn-1Y magnesium alloy, the split Hopkinson pressure bar (SHPB) apparatus was used to testing the true stress-true strain curves under the high strain rates of 1000, 1500 and 2200 s(-1) of as-extruded Mg-3Zn-1Y magnesium alloy. The OM and SEM were used to analysis the micorstructure evolution and fracture surface morphology of the alloy. The true reason behind the anisotropic phenomenon was revealed based on the deformation mechanism of highly basal-textured magnesium alloy. The results demonstrate that the as-extruded Mg-3Zn-1Y magnesium alloy exhibits pronounced anisotropy during compression according to the loading direction. The anisotropy of the as-extruded Mg-3Zn-1Y magnesium alloy are arised from the variety of the deformation mechanisms. When the loading direction is along extrusion direction, the predominant deformation mode changes from extension twinning at a lower strain to prismatic slip at a higher strain. While compressed along extrusion radial direction (ERD), the predominant deformation mode changes from contraction twinning to a coordination of basal and second order pyramidal slip with the increasing of strain.

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