| Abstract Scope |
Polycrystalline magnesium (Mg) and its alloys have been widely investigated to better understand and improve their mechanical properties including ductility, formability, yield anisotropy, elevated temperature performance, to name a few. However, significant questions remain as to how these materials behave under ultra-high strain-rate loading conditions, especially at elevated temperatures. In view of this, in the present study, elevated temperature combined pressure-and-shear plate impact experiments are employed to investigate the dynamic shearing resistance of polycrystalline commercially pure (99.9%) magnesium at strain-rates in excess of 105 s-1, temperatures up to 500˚C, and shear strains >100%. The results of the study provide important insights into the shearing resistance of polycrystalline pure Mg under extreme thermomechanical loading and its relationship to evolution of various inelastic deformation modes – dislocation-mediated slip, deformation twinning, and geometric strain softening -- with different mechanisms becoming dominant at different levels of inelastic strains and test temperatures. |