Optimization of strength and ductility in an as-extruded Cu–15Ni–8Sn alloy by the additions of Si and Ti

A superior combination of strength-ductility was obtained in an as-extruded Cu–15Ni–8Sn alloy through controlling microstructural evolution during hot extrusion by the additions of Si and Ti. The results show that the additions of Si and Ti favor the formation of Ni16Si7Ti6 particles, which help to promote the nucleation of dynamic recrystallization during hot extrusion. Moreover, the Ni16Si7Ti6 nanoparticles can retard the growth of the recrystallized grains during subsequently air-cooling. The as-extruded alloy with an extrusion ratio of 17 shows a completely fine recrystallized microstructure, which gives rise to a super combination of tensile strength of 909 MPa and elongation of 30%. The as-extruded Cu–15Ni–8Sn alloy with the additions of Si and Ti shows even comparable strength–ductility synergy with the heat-treated Cu–15Ni–8Sn alloy.