Transformation-reinforced high-entropy alloys with superior mechanical properties via tailoring stacking fault energy

Liu, Shaofei; Wu, Yidong; Wang, H.T.; Lin, Weitong; Shang, Yuanyuan; Liu, J.B.; An, Ke; Liu, X.J.; Wang, H.

doi:10.1016/j.jallcom.2019.04.035

Cited by 131 publications

(42 citation statements)

References 63 publications

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“…The present trends are in accordance with the previously reported trends in both experimental and theoretical estimates[57][58][59][60][61]. Specifically, for the CrCoNi MEA, the calculated SFE is -24 mJ/m 2 for the PM state and -29 mJ/m 2 for the FM state, respectively.…”

supporting

confidence: 92%

“…Thereby, the experimentally estimated is always positive as decided by the ∝ 1 relationship. Furthermore, in metastable alloys, in response to external stress, dislocations are easily separated into wide SF ribbons, even at very small strains [65], and therefore, it is not a trivial task to measure the partial separation [57], as compared to the cases of pure fcc metals. Smith et al [66] measured the partial separation of the a/2<110>{111} 60° mixed dislocations in CrMnFeCoNi HEA and found significantly large variations in .…”

Section: Stacking Fault Energymentioning

confidence: 99%

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Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

Yang

Tian

et al. 2020

SSRN Journal

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In order to efficiently explore the nearly infinite composition space in multicomponent solid solution alloys, it is important to establish predictive design strategies and use computation-aided methods. In the present work, we demonstrated the density functional theory calculations informed design routes for realizing transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) in Cr-Co-Ni medium entropy alloys (MEAs). We systematically studied the effects of magnetism and chemical composition on the generalized stacking fault energy surface (-surface) and showed that both chemistry and the coupled magnetic state strongly affect the -surface, consequently, the primary deformation modes. Based on the calculated effective energy barriers for the competing deformation modes, we constructed composition and magnetism dependent deformation maps at both room and cryogenic temperatures. Accordingly, we proposed various design routes for achieving desired primary deformation modes in the ternary Cr-Co-Ni alloys. The deformation mechanisms predicted by our theoretical models are in nice agreement with available experimental observations in literature. Furthermore, we fabricated two non-equiatomic Cr-Co-Ni MEAs possessing the designed TWIP and TRIP effects, showing excellent combinations of tensile strength and ductility. Corresponding authors: a Song Lu, songlu@kth.se b Yanzhong Tian,

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supporting

confidence: 92%

Section: Stacking Fault Energymentioning

confidence: 99%

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

Yang

Tian

et al. 2020

SSRN Journal

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“…The SFEs of fcc austenitic steels, particularly of high-Mn steels, have empirically been known to correlate with their deformation behaviors [63][64][65][66][67]. Also for 3d-transitionelement-based HEAs, their SFEs have also been measured in experiments [8,17,26,[68][69][70][71] and computed based on firstprinciples simulations [72][73][74][75][76][77][78][79][80][81][82][83][84]. While the impact of C atoms on the SFEs of HEAs has also been discussed in experimental fcc hcp FIG.…”

Section: A Stacking-fault Energymentioning

confidence: 99%

Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

Ikeda

Tanaka

Neugebauer

et al. 2019

Phys. Rev. Materials

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Interstitial alloying in CrMnFeCoNi-based high-entropy alloys is known to modify their mechanical properties. Specifically, strength can be increased due to interstitial solid-solution hardening, while simultaneously affecting ductility. In this paper, first-principles calculations are carried out to analyze the impact of interstitial C atoms on CrMnFeCoNi in the fcc and the hcp phases. Our results show that C solution energies are widely spread and sensitively depend on the specific local environments. Using the computed solution-energy distributions together with statistical mechanics concepts, we determine the impact of C on the phase stability. C atoms are found to stabilize the fcc phase as compared to the hcp phase, indicating that the stacking-fault energy of CrMnFeCoNi increases due to C alloying. Using our extensive set of first-principles computed solution energies, correlations between them and local environments around the C atoms are investigated. This analysis reveals, e.g., that the local valence-electron concentration around a C atom is well correlated with its solution energy.

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“…In face-centered cubic (FCC) metals, SFs are interruptions in the perfect (ABCABC) sequential layering of the (111) crystallographic planes, formed by either dissociation of a perfect dislocation into two partial dislocations, or by emission of partial dislocations from grain boundaries 4 . Typically the width of SFs are measured using weak beam-dark field diffraction in the transmission electron microscope (TEM) [5][6][7][8] , however SFs have also been resolved using electron contrast channel imaging (ECCI) in the scanning electron microscope (SEM) [9][10][11][12] .…”

mentioning

confidence: 99%

“…Recently a number of studies have investigated low SFE high entropy alloys using in-situ neutron diffraction, demonstrating the ability to relate macroscopic stress-strain response with multiple deformation mechanisms 5,[23][24][25][26][27][28] . Thus, to gain a better understanding of the deformation behavior in both phases, the strengthening in the γ-f.c.c.…”

mentioning

confidence: 99%

Correlating work hardening with co-activation of stacking fault strengthening and transformation in a high entropy alloy using in-situ neutron diffraction

Frank

Nene

Chen

et al. 2020

Sci Rep

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Transformation induced plasticity (TRIP) leads to enhancements in ductility in low stacking fault energy (SFE) alloys, however to achieve an unconventional increase in strength simultaneously, there must be barriers to dislocation motion. While stacking faults (SFs) contribute to strengthening by impeding dislocation motion, the contribution of SF strengthening to work hardening during deformation is not well understood; as compared to dislocation slip, twinning induced plasticity (TWIP) and TRIP. Thus, we used in-situ neutron diffraction to correlate SF strengthening to work hardening behavior in a low SFE Fe40Mn20Cr15Co20Si5 (at%) high entropy alloy, SFE ~ 6.31 mJ m−2. Cooperative activation of multiple mechanisms was indicated by increases in SF strengthening and γ-f.c.c. → ε-h.c.p. transformation leading to a simultaneous increase in strength and ductility. The present study demonstrates the application of in-situ, neutron or X-ray, diffraction techniques to correlating SF strengthening to work hardening.

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Transformation-reinforced high-entropy alloys with superior mechanical properties via tailoring stacking fault energy

Cited by 131 publications

References 63 publications

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

Correlating work hardening with co-activation of stacking fault strengthening and transformation in a high entropy alloy using in-situ neutron diffraction

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