A high-entropy alloy with hierarchical nanoprecipitates and ultrahigh strength

作者：Fu, Zhiqiang; Jiang, Lin; Wardini, Jenna L.; MacDonald, Benjamin E.; Wen, Haiming; Xiong, Wei; Zhang, Dalong; Zhou, Yizhang; Rupert, Timothy J.; Chen, Weiping^*; Lavernia, Enrique J.^*

来源：Science Advances, 2018, 4(10): eaat8712.

DOI：10.1126/sciadv.aat8712

• COMPOSITIONALLY COMPLEX ALLOY
• MECHANICAL-PROPERTIES
• SOLID-SOLUTION
• TENSILE PROPERTIES
• MICROSTRUCTURE
• NANOCRYSTALLINE
• BEHAVIOR
• ELEMENTS

High-entropy alloys (HEAs) are a class of metallic materials that have revolutionized alloy design. They are known for their high compressive strengths, often greater than 1 GPa; however, the tensile strengths of most reported HEAs are limited. Here, we report a strategy for the design and fabrication of HEAs that can achieve ultrahigh tensile strengths. The proposed strategy involves the introduction of a high density of hierarchical intragranular nanoprecipitates. To establish the validity of this strategy, we designed and fabricated a bulk Fe25Co25Ni25Al10Ti15 HEA to consist of a principal face-centered cubic (fcc) phase containing hierarchical intragranular nanoprecipitates. Our results show that precipitation strengthening, as one of the main strengthening mechanisms, contributes to a tensile yield strength (sigma 0.2) of similar to 1.86 GPa and an ultimate tensile strength of similar to 2.52 GPa at room temperature, which heretofore represents the highest strength reported for an HEA with an appreciable failure strain of similar to 5.2%.

• 出版日期2018-10
• 单位华南理工大学