Microstructure and strain rate sensitivity in pure magnesium subjected to severe plastic deformation

Microstructure and strain rate sensitivity in pure magnesium subjected to severe plastic deformation (SPD) has been investigated by nanoindentation. SPD process can be used to refine grain structure for improving the strength of material by reducing the grain size. The magnesium was subjected to equal channel angular pressing up to four passes by route Bc. The mechanical properties were measured by Vickers hardness and nanoindentation, and the microstructure was observed by electron backscattered diffraction. The hardness test showed that the deformed sample exhibited harder than an annealed sample, and it also can be confirmed by the nanoindentation test. The strain rate sensitivity can be observed by nanoindentation with different time to load, and the result exhibited harder, higher in modulus value and deeper in the displacement of the indenter. It was occurred due to microstructure evolution on pure magnesium by high deformation level.