High-pressure torsion of pure magnesium: Evolution of mechanical properties, microstructures and hydrogen storage capacity with equivalent strain

  Pure Mg (99.9%) is processed by high-pressure torsion (HPT) at room temperature. The hardness behavior with imposed strain is similar to pure Al (99.99%), having a hardness maximum followed by a steady state. HPT processing increases the hardness and tensile strength. A bimodal microstructure with an average grain size of ∼1 μm is developed by HPT with some grains free of dislocations. Hydrogen absorption is improved by HPT after 10 revolutions, and a total hydrogen absorption of 6.9 wt.% is achieved.