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 Fe25Co25Ni25Al10Ti115 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 (σ0.2) of ~1.86 GPa and an ultimate tensile strength of ~2.52 GPa at room temperature, which heretofore represents the highest strength reported for an HEA with an appreciable failure strain of ~5.2%.
Z. Fu et al., "A High-Entropy Alloy with Hierarchical Nanoprecipitates and Ultrahigh Strength," Science Advances, vol. 4, no. 10, American Association for the Advancement of Science, Oct 2018.
The definitive version is available at https://doi.org/10.1126/sciadv.aat8712
Materials Science and Engineering
Keywords and Phrases
Aluminum alloys; Cobalt alloys; Compressive strength; Entropy; High strength alloys; Iron alloys; Precipitation (chemical); Titanium alloys, Face centered cubic phase; High entropy alloys; Metallic material; Precipitation strengthening; Strengthening mechanisms; Tensile yield strength; Ultimate tensile strength; Ultrahigh strength, Tensile strength
International Standard Serial Number (ISSN)
Article - Journal
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