Enhanced strength-ductility synergy in an ultra-strong copper alloy via coherent nanoprecipitates and stress-induced twinning
Kui Jin, Jiangnan Li, Caiju Li, Qiong Lu, Zunyan Xu, Yuanqi You, Peng Gao, Liang Liu, Jianhong Yi, J. Eckert
Abstract
Deformation twins (DTs) and stacking faults (SFs) are rarely found in Cu-20Ni-20Mn alloy, which limits further strengthening of alloy. Here, we report ultra-strong Cu-20Ni-20Mn alloy prepared by introducing a high density of coherent nanoprecipitates. The ultimate tensile strength (UTS) of alloy can be largely enhanced to 1624.7 ± 14.7 MPa, while maintaining an acceptable elongation of 7.3 ± 0.5%. We find that the coherent nanoprecipitates contribute to an ultra-high true stress up to about 1740 MPa, which facilitate the formation of DTs. The strength and ductility improvement stems from the synergistic effect of dislocations, nanoprecipitates and DTs.