Fabrication of immiscible Cu-V alloy by high-pressure torsion.

Abstract

This study describes the fabrication of immiscible Cu-V alloys through the application of high-pressure torsion (HPT). For this purpose, stacked Cu/V/Cu disks were subjected to HPT from 0.5 to 250 turns under a pressure of 6.0 GPa at room temperature. The V layers became thinner and fragmented with increasing numbers of HPT turns but finally mixed well with the Cu matrix throughout the disk samples. After 200 turns HPT processing, the nanostructured Cu-V alloy displays a submicron level heterostructure with a mixture of coarser grains (~100 nm and high Cu content) and finer grain (~20-30 nm and high V content). An ultimate tensile strength (UTS) of 1300 MPa with 3.5% elongation was achieved in a sample subjected to 200 turns HPT processing and post-HPT annealing at 773 K for 1 hr. Thus, the HPT-processed immiscible Cu-V alloy achieved not only a significant microstructural refinement but also a remarkable strength enhancement through the solid mixing of Cu and V at room temperature.