FCC to BCC transformation-induced plasticity based on thermodynamic phase stability in novel V10Cr10Fe45CoxNi35−x medium-entropy alloys

Jo, Yong Hee; Choi, Wookjin; Kim, Donggeun; Zargaran, Alireza; Sohn, Seok Su; Kim, Hyoung Seop; Lee, Byeong-Joo; Kim, Nack J.; Lee, Sung Hak

doi:10.1038/s41598-019-39570-y

Cited by 89 publications

(10 citation statements)

References 55 publications

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“…As mentioned above, ε-martensite plates can act as one of the nucleation sites of α ' -martensite during plastic deformation [25]. This phenomenon was reported by Jo et al [27] where they observed nucleation of bcc phases on the hcp phases in the V 10 Cr 10 Fe 45 Co 30 Ni 5 alloy system. A similar phenomenon is observed in the present study where α ' -martensite (bcc) is nucleated inside DTs where the ε-martensite (hcp) has already been formed as shown in Fig.…”

Section: Phase Transformationmentioning

confidence: 52%

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

Ondicho

Alunda²,

Owino

et al. 2020

Acta Metall. Sin. (Engl. Lett.)

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A transformation-induced plasticity phenomenon in Fe 65 (CoCrMnNi) 35 medium-entropy alloy was investigated. According to the X-ray diffraction patterns, the as-cast specimen contains a single-phase face-centered cubic (fcc), while low-temperature annealing at 500 °C and 600 °C leads to the introduction of a body-centered cubic (bcc) phase as a secondary phase. Further increment of the annealing temperature to above 700 °C eliminates the bcc phase, and the microstructure was found to contain a single-phase fcc. At 20% true strain, an fcc-to-bcc phase transformation is observed; whereas, at 28% true strain, an fccto-hcp phase transformation takes place as an additional deformation mechanism. This strain-induced phase transformation phenomenon leads to improved tensile properties of this alloy.

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Section: Phase Transformationmentioning

confidence: 52%

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

Ondicho

Alunda²,

Owino

et al. 2020

Acta Metall. Sin. (Engl. Lett.)

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“…Crystallographic data ICSD-52258 were used to calculate the XRD profile of Fe-bcc ( a Fe = 2.8665 Å), while ICSD-44387 was used for Ag-fcc ( a Ag = 4.0855 Å). Note that a fcc structure can be thought as an expanded bcc structure along the c -axis by a factor of , , such that the two crystal structures satisfy the relation , which complicate XRD characterization because the XRD profile of bcc-Fe is very similar to the subset of polycrystalline fcc-Ag up to 2θ > 130° with a difference Δ(2θ) < 1.5°, as seen in the simulated XRD profiles for this transition in Figure S9. However, as seen in Figure b,d, Fe-bcc and Ag-fcc exhibit preferred orientations along the close-packed (110) and (111) planes, respectively, so that it is still possible to use XRD to distinguish Fe from Ag phases.…”

Section: Resultsmentioning

confidence: 99%

Rational Compositional Control of Electrodeposited Ag–Fe films

Sun

Zangari

2020

Inorg. Chem.

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Some alloys are very difficult to electrodeposit, due to problems such as the large difference in the equilibrium potentials and/or deposition kinetics of the alloy components, as well as the bath instability due to the spontaneous reactions in the bulk electrolyte. The Ag–Fe system is one of those. In this work, a novel alkaline citrate–dimethylhydantoin (DMH) complex has been used to synthesize thermodynamically immiscible Ag–Fe alloy films. The large difference in standard potentials and deposition kinetics of Ag and Fe is partially resolved by complexing Ag(I) with DMH, while the instability caused from spontaneous reduction of Ag(I) by Fe(II) was partially resolved by adding 1% Fe3+, based on the philosophy of the mixed potential theory. Furthermore, a paradigm for control of film composition is developed, based on the mass-transfer coefficient ratio, tested with various bath constitutions. Uniform and high-quality films are obtained, with a composition error of <4 at. % comparing with the predicted values. Electrochemical reactions involved in the deposition baths were systematically investigated using cyclic voltammetry, showing satisfactory agreement with the predicted deposition potentials calculated by equilibrium thermodynamics. The films deposited at high overpotential are proven to be biphasic, containing Ag-fcc and Fe-bcc phases, with a trend of decreasing crystallinity at increasing overpotentials when deposited at constant deposition time. A narrow transition potential range (<0.05 V) from the onset of Fe deposition to its limiting current condition was observed.

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“…However, the emergence of non-equiatomic HEAs have shown new possibilities in terms of exploring mechanical properties and phase stability of these alloys. Many of the reported non-equiatomic HEAs were metastable, and facilitate phase transformation under externally applied stress, thus resulting in the TRIP effect 22 , 23 . TRIP assisted deformation of FCC-HEAs and BCC-HEAs have been actively studied recently 13 , 24 – 27 .…”

Section: Discussionmentioning

confidence: 99%

Exceptionally high strain-hardening and ductility due to transformation induced plasticity effect in Ti-rich high-entropy alloys

Eleti

Klimova

Tikhonovsky

et al. 2020

Sci Rep

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Their experimental observations confirmed the Bo-Md approach could be useful in terms of designing new Ti-rich BCC-HEAs. It should be noted however, the relevance and validity of these predictions based on this controlled alloy strategy for other alloys is not yet fully explored. The primary objective of the present study is to investigate deformation mechanisms of new Ti-rich BCC-HEAs designed using the Bo-Md approach. Given the vast compositional space of HEAs, appropriate alloying elements must be chosen in order to exploit the required properties in terms of designing new HEAs. Here, we designed two new Ti-rich HEAs having chemical compositions Ti 38 Zr 25 Hf 25 Ta 7 Sn 5 , Ti 38 Zr 25 Hf 25 Ta 10 Sn 2 to compare them with the Ti 35 Zr 27.5 Hf 27.5 Nb 5 Ta 5 alloy. It is known that an addition of Sn increases β stability of Ti-alloys 14-16. Furthermore, the combination of Ta and Sn alloying elements were previously reported to have advantages in terms of tuning the martensite formation temperature 15. Therefore, in the present study, first we chose the Ti 35 Zr 27.5 Hf 27.5 Nb 5 Ta 5 alloy 13 as a base reference and replaced Nb with Sn, and adjusted the overall chemical compositions as Ti 38 Zr 25 Hf 25 Ta 10 Sn 2 , and Ti 38 Zr 25 Hf 25 Ta 7 Sn 5 to make sure the alloys positions are maintained along or near the M s ~ RT domain, on the Bo-Md diagram. Latter, the obtained alloys were characterized and their deformation mechanisms were systematically investigated.

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FCC to BCC transformation-induced plasticity based on thermodynamic phase stability in novel V10Cr10Fe45CoxNi35−x medium-entropy alloys

Cited by 89 publications

References 55 publications

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

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

Rational Compositional Control of Electrodeposited Ag–Fe films

Exceptionally high strain-hardening and ductility due to transformation induced plasticity effect in Ti-rich high-entropy alloys

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