Formation of bulk nanostructured Al₃Ni from elemental micropowders using high-pressure torsion

The formation of bulk nanograined Al₃Ni intermetallics from elemental micro-powder mixtures of Al-25 mol.% Ni are studied after processing by high-pressure torsion (HPT) for various turns at 473 K and at 573 K. It is found that nanograined Al₃Ni intermetallics with high angles of misorientation are produced at temperatures well below the melting temperature. The fraction of Al₃Ni intermetallics increases by increasing the shear strain and increasing the HPT processing temperature. During HPT, both Ni and Al atoms diffuse significantly in each other with a diffusion coefficient well comparable to the atomic interdiffusion in the Al₃Ni intermetallic at its melting temperature.