A high-entropy alloy with hierarchical nanoprecipitates and ultrahigh strength.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30333993.
- Also identified by DOI 10.1126/sciadv.aat8712 and PMC identifier 6184785.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
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 Fe<sub>25</sub>Co<sub>25</sub>Ni<sub>25</sub>Al<sub>10</sub>Ti<sub>15</sub> 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 (σ<sub>0.2</sub>) 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%.