Microstructural origins of impact resistance of AlCoCrFeNi2.1 eutectic high-entropy alloy

作者：Li, Jiansheng; Zhou, Jian; Liu, Yanfang; Wei, Kang; Liu, Jianfeng; Xi, Yichun; Li, Zhumin; Liu, Tong; Jiang, Wei^*

来源：Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing , 2024, 890: 145921.

DOI：10.1016/j.msea.2023.145921

• Dynamic loading
• Eutectic high -entropy alloy
• Strain hardening
• Strain rate hardening
• Dislocation slip

In this work, the mechanical properties and related deformation mechanisms of AlCoCrFeNi2.1 eutectic highentropy alloy (EHEA) under dynamic loading were systematically investigated at a medium strain rate range from 500 to 1500 s-1. The EHEA presents significant strain rate hardening and continuous strain hardening without any adiabatic shear bands. The yield strength increases from 803.8 MPa at 500 s-1 to 1006.8 MPa at 1500 s-1. The strain rate sensitivity and strain hardening exponent were evaluated to be 0.198 and 0.567-0.683, respectively, responding for the superior capability to withstand dynamic loading. Post-deformation microstructural analysis reveals that increased strain rate induces higher dislocation density. In the FCC phase, dislocation planar slip at {111} planes dominates at 500 and 1000 s-1, while high dense dislocation walls (HDDWs) form at 1500 s-1 from coplanar slip along {111} planes. In the BCC phase, high dense nanoprecipitates result in a significant precipitate-strengthening effect, featured by arrow-shaped dislocations, dislocation loops and dislocation tangles.

• 单位
  南昌航空大学; 南京理工大学