Room- and cryogenic-temperature compressive properties for the three V10Cr10Co30FexNi50-x (x = 40, 45, 50) high entropy alloys are investigated under quasi-static and dynamic loading conditions. The face-centered cubic (FCC) stability, which is estimated by the calculation of Gibbs free energy difference between FCC and body-centered cubic (BCC) phases, decreases in increasing order of Fe content. The 40Fe and 45Fe alloys consist of FCC single phase, whereas the 50Fe alloy is composed of a duplex structure with ~95 vol% of body-centered cubic (BCC) lath martensite. Under the quasi-static loading condition at room temperature, the dislocation slip prevails in the 40-at.%-Fe-containing alloy, while the twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) are activated in the other alloys. The decrease in testing temperature lowers the FCC stability, activating both TWIP and TRIP mode. Under the dynamic loading, the magnitude of TWIP effect enhances, but that of TRIP effect reduces in comparison to the quasi-static loading. The adiabatic heating induced from the dynamic loading increases the FCC stability, thereby resulting in the reduced TRIP effect. Despite the increased stability, the TWIP occurs more actively because the dynamic loading enables the increased flow stress to readily exceed the critical stress required for TWIP. These variations of deformation mechanisms according to the FCC stability, testing temperature, loading rate, adiabatic heating effect, and increased flow stress effect are systematically correlated by the shifting of stability on the slip-TWIP-TRIP mechanism band.
Bibliographical noteFunding Information:
This work was supported by the Korea University Grant for Prof. S.S. Sohn, by Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT ( 2016M3D1A1023384 ), and by the Brain Korea 21 PLUS Project for Center for Creative Industrial Materials.
© 2021 Elsevier B.V.
- Dynamic compressive test
- High entropy alloy (HEA)
- Stability of FCC phase
- Transformation-induced plasticity (TRIP)
- Twinning-induced plasticity (TWIP)
ASJC Scopus subject areas
- General Materials Science
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering