Simultaneous enhancement of strength and ductility via microband formation and nanotwinning in an L12-strengthened alloy

Yang，Lu1; Liang，Dingshan1; Cheng，Zhuo1; Duan，Ranxi1; Zhong，Chuanxin1; Luan，Junhua2; Jiao，Zengbao3; Ren，Fuzeng1

2022

10.1016/j.fmre.2022.05.024

Fundamental Research   Impact Factor & Quartile

2667-3258

Metallic alloys with high strength and large ductility are required for extreme structural applications. However, the achievement of ultrahigh strength often results in a substantially decreased ductility. Here, we report a strategy to achieve the strength-ductility synergy by tailoring the alloy composition to control the local stacking fault energy (SFE) of the face-centered-cubic (fcc) matrix in an L1-strengthened superlattice alloy. As a proof of concept, based on the thermodynamic calculations, we developed a non-equiatomic CoCrNi(AlNb) alloy using phase separation to create a near-equiatomic low SFE disordered CoCrNi medium-entropy alloy matrix with in situ formed high-content coherent Ni(Al, Nb)-type ordered nanoprecipitates (∼ 12 nm). The alloy achieves a high tensile strength up to 1.6 GPa and a uniform ductility of 33%. The low SFE of the fcc matrix promotes the formation of nanotwins and parallel microbands during plastic deformation which could remarkably enhance the strain hardening capacity. This work provides a strategy for developing ultrahigh-strength alloys with large uniform ductility.

L12-strengthened superlattice alloy Microbands Nanotwins Stacking fault energy Strain hardening

English

First ; Corresponding

National Natural Science Foundation of China[52122102];

2-s2.0-85133356402

Scopus

1.Department of Materials Science and Engineering,Southern University of Science and Technology,Shenzhen,Guangdong,China
2.Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong,China
3.Department of Mechanical Engineering,The Hong Kong Polytechnic University,Hong Kong,China

Yang，Lu,Liang，Dingshan,Cheng，Zhuo,et al. Simultaneous enhancement of strength and ductility via microband formation and nanotwinning in an L12-strengthened alloy[J]. Fundamental Research,2022.

Yang，Lu.,Liang，Dingshan.,Cheng，Zhuo.,Duan，Ranxi.,Zhong，Chuanxin.,...&Ren，Fuzeng.(2022).Simultaneous enhancement of strength and ductility via microband formation and nanotwinning in an L12-strengthened alloy.Fundamental Research.

Yang，Lu,et al."Simultaneous enhancement of strength and ductility via microband formation and nanotwinning in an L12-strengthened alloy".Fundamental Research (2022).