Enhanced microhardness in nanocomposite Ti60Cu14Ni12Sn4Ta10 processed by high pressure torsion

Nanostructured Ti60Cu14Ni12Sn4Ta10 alloys have been obtained by (i) arc-melting (AM) the pure elements and (ii) AM followed by severe plastic deformation induced by high pressure torsion (HPT). Scanning electron microscopy (SEM) reveals that the AM specimen consists of a dendrite–eutectic structure. After the HPT, the center of the disks exhibits a microstructure similar to the AM specimen but with strongly deformed dendrites and the lamellae become refined and intermixed as the distance from the disk center increases. At the edge of the HPT disks the dendritic/eutectic morphology is no longer observed by SEM. The Vickers microhardness is higher in the HPT disks as compared to the AM samples. This result is discussed in terms of the peculiar morphologies and nanostructures achieved after each processing route.