Enhancement of Strength and Hardness in Copper-Chromium-Zirconium Alloy Using Single-Pass Multi-Angular Twist Channel Extrusion: A Microstructural and Deformation Study

Herein, the strength and hardness of copper-chromium-zirconium alloy are enhanced in a single pass by a severe plastic deformation (SPD) technique called the multiangular twist channel extrusion (MATE) process. In equal channel angular pressing (ECAP) and twist extrusion (TE), requisite strain and uniformity are achieved through several extrusion passes. MATE is a single-pass novel SPD technique developed by integrating TE with the ECAP followed by a direct channel zone. The deformation behavior of metal in the MATE process is elucidated through experimental and microstructural studies conducted in each zone. The MATE-processed Cu-Cr-Zr alloy achieves a hardness of 184.4 Hv and a tensile strength of 645.2 MPa, reflecting an increase of 80.43% and 69.7%, respectively, relative to the annealed condition. The electrical conductivity of the MATE-processed Cu-Cr-Zr alloy decreases to 74.29% International Annealed Copper Standard. The electron backscatter diffraction investigation reveals an average grain size of 2.8 mu m, with 61% comprising low-angle grain boundaries, while the calculated dislocation density, from X-ray diffraction analysis, is 3.93 x 1014 m-2. The transmission electron microscopy image verifies the existence of dislocations and precipitates in the Cu-Cr-Zr alloy. The experimental and microstructural findings in each zone have aligned effectively.