Fracture characteristic of a Mg-Gd-Y alloy compressed at high strain rate and sub-zero temperature

摘要

In this paper, an as-extruded Mg-10Gd-2Y-0.5Zr alloy was compressed at 3265 s~(-1) and -20°C using a split Hopkinson pressure bar (SHPB) machine. Details about the initial texture and the lattice parameters of the as-extruded alloy were obtained by pole figures combined by orientation distribution function (ODF) and X-ray diffraction (XRD) Rietveld refinement method, respectively. It can be obtained that the maximum average orientation factor being 0.297 can be obtained at 45o angled to the extruded direction that is the force axis, resulting in the fracture of the impact compressed sample along a plane orientated at an angle of ～45° to the compression axis. Analysis of the fracture reveals that the fracture forms near the periphery of one face of the specimen and then penetrates into the bulk material subsequently meet near the other face. Even though the local shear deformation exists in the compressed sample, the fracture of the as-extruded Mg-10Gd-2Y-0.5Zr alloy compressed at 3265 s~(-1) and -20°C is not caused by forming the adiabatic shear band (ASB).