A study on cryogenic temperature ECAP on the microstructure and mechanical properties of Al–Mg alloy

Equal channel angular pressing (ECAP) is an established technique to refine the grain size of various metals and alloys with improved mechanical properties. Annealed billets of Al–Mg were pressed at room and cryogenic temperature using Bc route in an equal channel angular die of 10 mm channel diameter. The billets were pressed up to a maximum of 14 passes. The microstructure evolution after different passes was studied by TEM. The effect of pressing temperature (room and cryogenic temperature) employed during pressing on the mechanical properties was studied by nanoindentation technique. The deformation parameters such as strain rate sensitivity (m) and activation volume (V⁎) of the alloy pressed at different temperature were also evaluated. In addition, plastic deformation behavior was also studied by cyclic nanoindentation on the samples. The present analysis showed that the hardness of Al–Mg alloy pressed in cryogenic condition was lower than that at room temperature.