Ultrahigh-strength Cu-10Fe-0.2Mg in situ composites via ultra-nano precipitation within nanolamellar architectures

Cu-Fe in situ composites face Hall-Petch strengthening saturation when Fe filaments reach nanoscale dimensions. The present study addresses this limitation through a strategy of “ultra-nano precipitation within nanolamellar architectures”. By adding 0.2 wt% Mg to a Cu-10Fe alloy and applying multi-stage thermo-mechanical processing, a Cu-10Fe-0.2Mg in situ composite was developed, featuring ultrafine CuMg₂ nanoprecipitates (∼6.8 nm) embedded in the Cu nanolamellar matrix. This optimized material achieves a 23 % strength enhancement compared to its Mg-free counterpart, while retaining 96 % of the base conductivity and comparable uniform elongation. The improvement in mechanical properties can be attributed to the Orowan strengthening effect from the introduced CuMg₂ nanoprecipitates and their ability to promote work hardening. This ultra-nano precipitation within nanolamellae strategy is envisaged to be readily adaptable to other Cu-bcc in situ composites, offering broad implications for next-generation material engineering.