Experimental investigation and phase diagram of CoCrMnNi–Fe system bridging high-entropy alloys and high-alloyed steels

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

“…The details and further discussion about this phase diagram can be found in Ref. [17]. The dotted line (red) shows the approximate composition and possible phases of Fe65 at different annealing temperatures.…”

“…Fe60 which is a single-phase fcc [17] was included in the present work to demonstrate the contributory effect of TRIP on the mechanical properties of Fe65. It was demonstrated by the previous work [17] that Fe60 did not undergo any phase transformation during plastic deformation and TWIP was confirmed to be the only additional strengthening mechanism. Figure 2b shows the YS, UTS, and TE as the composition changes from Fe60 to Fe65.…”

“…The details on how to measure the local strain are reported in Ref. [17]. The IPF images show a homogenous microstructure with equiaxed grains.…”

“…2a, b. It was reported that the main deformation mechanisms for Fe60 are slip and deformation twinning [17]. Therefore, the superior UTS and TE observed in Fe65 can be attributed to an additional strengthening mechanism during plastic deformation.…”

“…A recent investigation by Ref. [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.…”