Strain rate, and temperature dependent flow behavior and microstructure evolution of FeMnNiCo and (FeMnNiCo)95Mo5 high-entropy alloys

In this work, the effect of strain rate (10 −1 –10 3 s −1 ), temperature (77 and 293 K) and Mo addition on the compressive flow stress behavior and microstructure evolution of the fcc single-phase FeMnNiCo and (FeMnNiCo) 95 Mo 5 high entropy alloy systems was investigated. A detailed study performed by SEM and TEM revealed that, in addition to dislocation gliding, mechanical twinning occurred during the deformation. The addition of 5 at.% of Mo increases yield strength while decreasing the stacking fault energy in the fcc alloy, thereby enhancing its tendency to form twins. This deformation was particularly promoted at low temperatures and high strain rates. The mechanical testing was complemented by detailed microstructural characterization in order to establish the relationship between strain rate, temperature, deformation mechanisms, and microstructural evolution.