Microstructure and tensile properties of Co-free Fe4CrNi(AlTi) high-entropy alloys

Effects of Cr/Fe Ratio on Structural Evolution and Tensile Properties of the Fe75.7−xCrxNi15.1Al4.6Ti4.6 High‐Entropy Alloys

“…The results are the same in our previous work. [ 24 ] In summary, in those HEAs, the single FCC phase is stable at high VEC value, while the BCC‐related phases are stable at a relatively low VEC value.…”

“…It is worth mentioning that the content of larger solute atoms, such as Al and Ti, has changed in the similar HEAs, the solid‐solution hardening is also not the dominant mechanism. [ 16,24,35 ]…”

“…It is known that BCC/L2 1 phases are typically more brittle but stronger than FCC phase due to the difference in the number of their available slip systems. [16,23,24] In the current HEAs, as Cr/Fe ratio is increased, the volume fraction of BCC/L2 1 phases increases and yet the volume fraction of FCC phase decreases. Therefore, the ultimate tensile strength (σ u ) of the alloys can be approximately described by the simple rule of mixture, [50] that is…”

“…It is anticipated, in the HEAs containing the soft FCC and hard BCC phases, adjusting the relative amount of those phases has been regarded as an effective method to obtain desired combinations of strength and ductility of the HEAs, [ 16,21,23,24 ] as summarized in Table S1, Supporting Information. Fortunately, the VEC is found to be the physical parameter to control the phase stability for FCC or BCC solid solutions, that is, VEC ≥ 8.0 for FCC, 6.87 ≤ VEC < 8.0 for FCC plus BCC, and VEC < 6.87 for BCC plus B2.…”

“…[ 25 ] In other words, the effect of the VEC on the phase stability is vitally important for alloy design and for controlling the mechanical behavior of HEAs. [ 24 ] As shown in Table S2 of Supporting Information, for the Cr element, the VEC is 6, lower than 8 of Fe element. Thus, increasing Cr/Fe ratio of an alloy can decrease the VEC values, which can result in enhancing stability of BCC phase.…”