Enhanced Per-Pass Strengthening and Reduced Aging Time in Cu–Cr–Zr Alloy Bars Processed by ECAP with Pulsed Electromagnetic Loading

Cu–Cr–Zr alloys must combine high strength with high electrical conductivity. Reaching both at once is slow: equal channel angular pressing (ECAP) consumes many passes, and aging adds a further hour at temperature. Here a pulsed electromagnetic load was superimposed on ECAP (EMPF-ECAP) for a Cu–0.239Cr–0.126Zr alloy, and the microstructure, hardness and conductivity were compared with conventional ECAP at the same pass numbers. Four EMPF-ECAP passes raised the as-deformed hardness to 170.89 HV, above the 147.51 HV of four conventional passes. Aging at 450 °C for 0.5 h then gave a peak of 207.16 HV and 79.12%IACS. The conventional route required six passes and 1 h to reach 200.09 HV and 80.71%IACS. Electron backscatter diffraction indicates why. At a comparable grain size (8.68 against 8.99 µm), the pulsed specimens retained a lower recrystallized fraction, 20.3% against 39.4%. More of their deformation substructure survived aging, and the high-angle boundary fraction was lower, 54.7% against 81.8%. Compared with conventional ECAP, EMPF-ECAP reduced the number of passes from six to four and the aging time from 1 h to 0.5 h, reaching the same hardness in half the aging time with about 1.6%IACS lower conductivity.