Superior strength-ductility combination of a Co-rich CoCrNiAlTi high-entropy alloy at room and cryogenic temperatures
Abstract
In the present study, a Co-rich CoCrNi-AlTi high-entropy alloy was designed and fabricated by hot forging and 700 °C for 8 h annealing process. The microstructure of the resultant alloy was composed of three multicomponent-phases with the face-centered cubic (FCC) structure, hexagonal close-packed (HCP) structure and L12 structure, respectively. The alloy exhibited a remarkable combination of tensile yield strength (gigapascal scale) and plasticity (uniform strain over 30%) at both room and cryogenic temperatures. The cooperative operation of multiple mechanisms consisting of refined-grain strengthening, second-phase strengthening, precipitation strengthening, stacking faults and phase-transformation toughening was suggested to be responsible for the excellent mechanical response.
- Publication:
-
Materials Research Express
- Pub Date:
- March 2020
- DOI:
- 10.1088/2053-1591/ab7a64
- Bibcode:
- 2020MRE.....7c4001D
- Keywords:
-
- high-entropy alloys;
- multiple-phase microstructure;
- mechanical properties;
- strengthening and toughening mechanisms