Dynamic compressive property and failure behavior of extruded Mg-Gd-Y alloy under high temperatures and high strain rates

Abstract

For the purpose of investigating the dynamic deformational behavior and failure mechanisms of magnesium under high strain rates, the Split Hopkinson Pressure Bar (SHPB) was used for investigating dynamic mechanical properties of extruded Mg-Gd-Y Magnesium alloy at ambient temperature (300 K), 200 °C (473 K) and 300 °C (573 K) temperature. The samples after compression were analyzed by scanning electron microscope (SEM) and metallographic microscope. Dynamic mechanical properties, crack performance and plastic deformation mechanism of extruded Mg-Gd-Y Magnesium alloy along the extrusion direction (ED) were discussed. The results show that, extruded Mg-Gd-Y Magnesium alloy has the largest dynamic compressive strength which is 535 MPa at ambient temperature (300 K) and strain rate of 2826 s−1. When temperature increases, dynamic compressive strength decreases, while ductility increases. The dynamic compression fracture mechanism of extruded Mg-Gd-Y Magnesium alloy is multi-crack propagation and intergranular quasi-cleavage fracture at both ambient temperature and high temperature. The dynamic compressive deformation mechanism of extruded Mg-Gd-Y Magnesium alloy is a combination of twinning, slipping and dynamic recrystallization at both ambient temperature and high temperature.