4.6 Article

Effect of Cu-Rich Phase Precipitation on the Microstructure and Mechanical Properties of CoCrNiCux Medium-Entropy Alloys Prepared via Laser Directed Energy Deposition

期刊

ACTA METALLURGICA SINICA-ENGLISH LETTERS
卷 34, 期 11, 页码 1591-1600

出版社

CHINESE ACAD SCIENCES, INST METAL RESEARCH
DOI: 10.1007/s40195-021-01316-z

关键词

Medium-entropy alloys; Mechanical properties; Laser directed energy deposition; Misfit dislocations; Cu-rich phase

资金

  1. National Natural Science Foundation of China (NSAF) joint Fund [U2030102]
  2. National Natural Science Foundation of China [52071124]

向作者/读者索取更多资源

By increasing the Cu content in CoCrNiCux alloys, the microstructure transitions from a single matrix phase to a dual-phase structure, accompanied by a shift in tensile fracture behavior from brittle to plastic. This results in an increase in tensile strength and ductility. Nanoprecipitates and neatly arranged misfit dislocations contribute to enhancing the strength and plasticity of the alloy, while twins in the matrix phase and coordinated dual-phase structures further improve mechanical properties.
CoCrNiCux (x = 0.16, 0.33, 0.75, and 1) without macro-segregation medium-entropy alloys (MEAs) was prepared using laser directed energy deposition (LDED). The microstructure and mechanical properties of CoCrNiCux alloys with increasing Cu content were investigated. The results indicate that a single matrix phase changes into a dual-phase structure and the tensile fracture behaviors convert from brittle to plastic pattern with increasing Cu content in CoCrNiCux alloys. In addition, the tensile strength of CoCrNiCux alloys increased from 148 to 820 MPa, and the ductility increased from 1 to 11% with increasing Cu content. The nano-precipitated particles had a mean size of approximately 20 nm in the Cu-rich phase area, and a large number of neatly arranged misfit dislocations were observed at the interface between the two phases due to Cu-rich phase precipitation in the CoCrNiCu alloy. These misfit dislocations hinder the movement of dislocations during tensile deformation, as observed through transmission electron microscopy. This allows the CoCrNiCu alloy to reach the largest tensile strength and plasticity, and a new strengthening mechanism was achieved for the CoCrNiCu alloy. Moreover, twins were observed in the matrix phase after tensile fracture. Simultaneously, the dual-phase structure with different elastic moduli coordinated with each other during the deformation process, significantly improving the plasticity and strength of the CoCrNiCu alloy.

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

4.6
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