Consolidation of commercial pure aluminum powder by torsional-equal channel angular pressing (T-ECAP) at room temperature

In the present study, commercial pure aluminum powders were successfully consolidated to nearly full density by a combination of equal channel angular pressing (ECAP) and torsional deformation at room temperature. This new modification of ECAP is named as torsional-equal channel angular pressing (T-ECAP). A mechanism has been suggested to demonstrate the changes in porosities' shape, which leads to the porosities elimination during the T-ECAP process. Metallographic investigations have shown that the shape of the porosities have been changed from an elongated orientation in the ECAP process into near spherical shape in the T-ECAP process. Due to the subsequent torsional strains during the T-ECAP process, pores eliminated more effectively. Density and micro-hardness tests have shown superior values for the samples produced by the T-ECAP process than that of the samples produced using ECAP process, which can be improved by increasing the number of passes. Due to the existence of a variation in porosity from edge to center of the samples produced by both ECAP and T-ECAP processes, a variation in micro hardness in a same trend is also detected. Examination of the mechanical properties of the T-ECAP samples shows some moderate plastic deformation during the compression tests and exhibits high magnitude of ductility with respect to the ECAP samples.

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► Metallic powders consolidated at room temperature using T-ECAP process.
► T-ECAP samples show superior ductility and deform like bulk sample in compression.
► T-ECAP samples show higher density and hardness in comparison to ECAP samples.
► Porosity shape and population changed as they pass the rotating part of die.
► Great mechanical and diffusional bonding between particles can be formed.