4.7 Article

Enhanced tensile properties by heterogeneous grain structures and coherent precipitates in a CoCrNi-based medium entropy alloy

出版社

ELSEVIER SCIENCE SA
DOI: 10.1016/j.msea.2021.142440

关键词

High entropy alloys; Heterogeneous structures; Precipitates; Strain hardening; Strengthening; Ductility

资金

  1. National Key R&D Program of China [2017YFA0204402]
  2. NSFC Basic Science Center Program for Multiscale Problems in Nonlinear Mechanics [11988102]
  3. Strategic Priority Research Program of the Chinese Academy of Sciences [XDB22040503]

向作者/读者索取更多资源

A dual heterogeneous structure consisting of both heterogeneous grain structure and coherent L1(2) nanoprecipitates is achieved in a CoCrNi-based medium entropy alloy. Aging leads to an increase in the volume fraction of L1(2) phase and a decrease in the corresponding interspacing, resulting in enhanced heterogeneity. Unaged samples exhibit better tensile properties compared to alloys with homogeneous and heterogeneous grain structures. Aged samples demonstrate improved strength and ductility, with hetero-deformation-induced hardening playing a crucial role, particularly at the elasto-plastic transition stage.
A dual heterogeneous structure with both heterogeneous grain structure and coherent L1(2) nanoprecipitates was obtained in a CoCrNi-based medium entropy alloy (MEA) with chemical composition of Co34.5Cr32-Ni27.5Al3Ti3 (in at%). The volume fraction of L1(2) phase is observed to become higher and the corresponding interspacing becomes smaller after aging, resulting in a more severe heterogeneity. The unaged samples are found to have better tensile properties as compared to those for the CoCrNi MEA with homogeneous and het-erogeneous grain structures. The aged samples display an even better synergy of strength and ductility than the corresponding unaged samples. The hetero-deformation-induced hardening plays a more important role in the aged samples than in the unaged samples, especially at the elasto-plastic transition stage, producing higher density of geometrically necessary dislocations for better tensile properties. Multiple deformation twins, stacking faults and Lomer-Cottrell locks are the dominant deformation mechanisms for the unaged samples, while in-teractions between these defects and L1(2) nanoprecipitates play important roles in the aged sample, the shearing hardening mechanism is observed for L1(2) nano-particles.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据