Effect of Short-Range Ordering on the Strength-Ductility Synergy of Fine-Grained Cu–Mn Alloys at Different Temperatures

Uniaxial tensile tests were carried out at room temperature (RT) and 250 °C, respectively, to investigate the effect of short-range ordering (SRO) on the mechanical properties and deformation micromechanism of fine-grained (FG) Cu–Mn alloys with high stacking fault energy. The results show that at RT, with the increase in SRO degree, the strength of FG Cu–Mn alloys is improved without a loss of ductility, and corresponding deformation micromechanism is mainly manifested by a decrease in the size of dislocation cells. In contrast, at a high temperature of 250 °C, the SRO degree becomes violently enhanced with increasing Mn content, and the deformation microstructures thus transform from dislocation cells to planar slip bands and even to deformation twins, significantly enhancing the work hardening capacity of the alloys and thus achieving a better strength-ductility synergy of FG Cu–Mn alloys.