Abstract
Discs of microcrystalline magnesium reinforced wit Al2O3 nanoparticles were deformed by high-pressure torsion at room temperature. Hydrostatic pressure from 1 to about 4 GPa were used and discs were deformed from 0.5 up to 2 rotations.
The in-situ flow stress curves were obtained and transformed into resolved shear stress / resolved shear strain curves. In-situ stress-strain curves indicate some softening effects, which probably arise from recrystallisation.
Microstructure evolution was observed with methods of light microscopy and transmission electron microscopy. Radial dependence of the microstructure was also monitored with microhardness measurements. The high-pressure torsion deformation also affects the distribution of the reinforcing particles in the hexagonal matrix.