Simultaneously enhancing strength, ductility, and electrical conductivity in Cu-1Cr-0.1Zr alloy by heterogeneous microstructure

A novel layered heterogeneous microstructure, exhibiting a multiscale distribution of grain sizes and structural features, including nanocrystalline (NC), nanotwins (NT), nanoscale precipitates (NP), submicron crystalline (SC) and microcrystalline (MC), was successfully fabricated within the Cu-1Cr-0.1Zr alloy via solid solution (SS) treatment, aging treatment (AT), cold rolling (CR), and annealing treatment. The heterogeneous microstructure of the Cu-1Cr-0.1Zr alloy exhibits excellent strength, ductility, and electrical conductivity, mainly due to the synergistic effects between multi-scale grains formed during deformation, leading to significant hetero-deformation induced (HDI) stress and the Bauschinger effect, which simultaneously improves strength and ductility. Interestingly, annealing treatment to form recrystallized grain, SC and MC can improve electrical conductivity. This study provides an effective way to achieve synergistic effects between significant strength, good ductility, and remarkable electrical conductivity in copper alloys.