Theoretical evaluation of solid solution interaction in Fe (CoCrMnNi)100- medium- and high-entropy alloys

Effect of Bimodal Grain Size Distribution on the Strain Hardening Behavior of a Medium-Entropy Alloy

“…It is noteworthy that the friction stress of Fe50 in the present study is less than that of CoCrNi MEA (218 MPa) reported by Yoshida et al [33] and that equiatomic CoCrFeMnNi (194 MPa). This can be attributed to the less distorted crystal structure as the Fe content is increased from the classical equiatomic CoCrFeMnNi HEA as a result reduced atomic size misfit [34]. The HP coefficient of Fe50 is observed to be slightly less than that of equiatomic CoCrFeMnNi (490 MPa) and significantly more than that of the equiatomic CoCrNi (265 MPa) [33].…”

Revealing a Transformation-Induced Plasticity (TRIP) Phenomenon in a Medium-Entropy Alloy

“…This indicates that the fraction of retained bcc phase is so small to have any substantial effect on the mechanical properties of Fe65. The slight decrease of the YS can be ascribed to the solid solution interaction effect in regards to the increased Fe content in the Fe x (CoCrMnNi) 100−x system [13]. At higher Fe content, as is the case of Fe65, the atomic size misfit is greatly decreased which leads to a significant decrease of the lattice distortion as compared to the equiatomic CoCrF-eMnNi HEA.…”

“…Several strengthening mechanisms have been reported in HEAs and MEAs [11][12][13][14]. For instance, the widely studied equiatomic CoCrFeMnNi HEA and CoCrNi MEA have been reported to possess outstanding mechanical properties both 1 3 at room temperature and under cryogenic conditions [11,15].…”

“…For instance, the widely studied equiatomic CoCrFeMnNi HEA and CoCrNi MEA have been reported to possess outstanding mechanical properties both 1 3 at room temperature and under cryogenic conditions [11,15]. The excellent mechanical properties in these two alloy systems have been attributed to the solid solution hardening [12,13], grain boundary strengthening [14], and mechanical twinning [11,15]. A study of the deformation mechanisms of CoCrFeMnNi and CoCrNi having a similar grain size both at room temperature and cryogenic temperature (77 K) showed that during the early stages of plastic deformation slip is the dominant deformation mechanism.…”

“…[17] highlighted the possibility of bridging the gap between the high-entropy concept and the high-alloyed steels by increasing the Fe content in the equiatomic CoCrFeMnNi HEA from 20 to 60 at%. In this study, it was shown that even though the yield stress (YS) decreases as the Fe content increases due to a reduced solid solution strengthening effect [12,13], twinning-induced plasticity (TWIP) enhances the ultimate tensile strength (UTS) and the total elongation (TE), especially for the Fe60 alloy. This phenomenon is similar to that observed in TWIP steels, where the twin boundaries act as barriers to dislocation motion, thus impeding their motion, therefore improving their mechanical properties [18][19][20].…”