Extra-ductile and strong tin bronze alloy via high-density intragranular ultra-nano precipitation with minimal lattice misfit

Here we report an “intragranular ultra-nano precipitation” strategy to strongly plasticizing and simultaneously strengthen polycrystalline Cu alloys. Our strategy relies on a high density (more than 1023 m−3) and uniform dispersion of extremely fine Fe nanoprecipitates (5.0 ± 2.7 nm) with minimal lattice misfit (theoretically 0.69%) inside Cu grains. The intragranular dispersion of ultra-nano particles not only considerably enhance tensile ductility of a plasticity-poor tin bronze alloy more than 2 times, but also elevate tensile strength above 20% in the meantime, arising from more stable and greater work hardening. The superb plasticizing and hardening of this class of Cu alloy are based on minimal lattice misfit to achieve maximal precipitate dispersion and durable intragranular nanoprecipitation-dislocation interactions (i.e., dislocations cut through fully-coherent Fe nanoprecipitates and hence produce plastic deformation), and we envisage that this intragranular ultra-nano precipitation strategy may be applied to many other metallic alloys.