Enhancement of strength-ductility synergy in ultrafine-grained Cu-Zn alloy prepared by ECAP and subsequent annealing

A homogeneously ultrafine-grained (UFG) Cu-38 Zn alloy with an average grain size of 0.64 μm is successfully fabricated by equal channel angular processing (ECAP), which exhibits a significantly enhanced strength-ductility synergy. The strength enhancement can be attributed to grain refinement and dislocation strengthening. After annealing the ECAP processed alloy at 300 °C for 30 min, a further enhanced strength with almost unchanged ductility was achieved. This unusual annealing strengthens is associated with the solute/impurity segregation and precipitations inside the grains.