Back to Search
Start Over
Outstanding tensile properties of a precipitation-strengthened FeCoNiCrTi0.2 high-entropy alloy at room and cryogenic temperatures.
- Source :
-
Acta Materialia . Feb2019, Vol. 165, p228-240. 13p. - Publication Year :
- 2019
-
Abstract
- Abstract A FeCoNiCrTi 0.2 high-entropy alloy strengthened by two types of coherent nano-precipitates but with the same composition was fabricated, and its tensile properties at room (293 K) and cryogenic temperatures (77 K) and the corresponding defect-structure evolution were investigated. Compared with the single-phase FeCoNiCr parent alloy, the precipitation-strengthened FeCoNiCrTi 0.2 high-entropy alloy exhibits a significant increase in yield strength and ultimate tensile strength but with little sacrifice in ductility. Similar to the single-phase FeCoNiCr high-entropy alloy, the deformation behavior of this precipitation-strengthened FeCoNiCrTi 0.2 high-entropy alloy shows strong temperature dependence. When the temperature decreases from 293 K to 77 K, its yield strength and ultimate tensile strength are increased from 700 MPa to 860 MPa and from 1.24 GPa to 1.58 GPa, respectively, associated with a ductility improvement from 36% to 46%. However, different from the single-phase FeCoNiCr high-entropy alloy with a twinning-dominant deformation mode at 77 K, multiple-layered stacking faults with a hierarchical substructure prevail in the precipitation-strengthened FeCoNiCrTi 0.2 high-entropy alloy when deformed at 77 K. The mechanism of twinning inhibition in this precipitation-strengthened high-entropy alloy is the high energy barrier for twin nucleation in the ordered γ′ nano-particles. Our results may provide a guide for the design of tough high-entropy alloys for applications at cryogenic temperatures through combining precipitation strengthening and twinning/stacking faults. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13596454
- Volume :
- 165
- Database :
- Academic Search Index
- Journal :
- Acta Materialia
- Publication Type :
- Academic Journal
- Accession number :
- 134187726
- Full Text :
- https://doi.org/10.1016/j.actamat.2018.11.049