Deformation behaviour of ultrafine grained Mg-7Gd-5Y-1.2Nd-0.5Zr alloy under high strain rates

The mechanical behaviour of Mg-7Gd-5Y-1.2Nd-0.5Zr (wt. %) alloy with ultrafine grains was measured by split Hopkinson pressure bar method under the strain rates of 1000, 1500, and 2000 s(-1) at room temperature. Dynamic tests were carried out along extrusion direction (ED), transverse direction (TD), and normal direction (ND). The results demonstrated that the flow stress increased with the increase of strain rate, showing a positive strain rate strengthening effect. There was no obvious anisotropy in dynamic compression along ED, TD, and ND, which was caused by rare earth elements and multi-pass deformation. This led to the adoption of plastic deformation mode dominated by non-basal slip and participated by tension twinning.