Heavy carbon alloyed FCC-structured high entropy alloy with excellent combination of strength and ductility

Chen, L.B.; Wei, Ran; Tang, Kai; Zhang, J.; Jiang, F.; Lin, He; Sun, Jun

doi:10.1016/j.msea.2018.01.045

Cited by 172 publications

(53 citation statements)

References 23 publications

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“…In equiatomic CrMnFeCoNi, the addition of C atoms is known to increase the yield and the ultimate strengths [18,20,24] while also impacting ductility. Enhanced yield and ultimate strengths are also found for interstitialalloyed Cr 0.1 Mn 0.3 Fe 0.5 Co 0.1 [10] and Cr 0.1 Mn 0.4 Fe 0.4 Co 0.1 [25] without critical reduction of ductility. To fine tune the mechanical properties by interstitial alloying, an understanding of the fundamental mechanisms on the atomic scale is required.…”

Section: Introductionmentioning

confidence: 79%

“…Another promising direction to further improve the mechanical properties of HEAs is interstitial alloying, e.g., with C. The impact of interstitial C atoms in HEAs has been investigated in several previous experimental studies [10,16,18,[20][21][22][23][24][25][26][27]. In equiatomic CrMnFeCoNi, the addition of C atoms is known to increase the yield and the ultimate strengths [18,20,24] while also impacting ductility.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 79%

Section: Introductionmentioning

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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“…Significant research efforts have been devoted to studying the mechanical properties of HEAs for a variety of engineering applications. Even though HEAs vary widely from the constituent elements and their compositions, many of them commonly show useful mechanical properties such as high hardness values [22][23][24][25], yielding stresses [26][27][28], fatigue resistance [29][30][31], and irradiation resistance [32,33].…”

Section: Introductionmentioning

confidence: 99%

Semiconducting SiGeSn high-entropy alloy: A density functional theory study

Wang

Liu

Huang

2019

Journal of Applied Physics

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High-entropy alloys (HEAs), which have been intensely studied due to their excellent mechanical properties, generally refer to alloys with multiple equimolar or nearly equimolar elements.According to this definition, Si-Ge-Sn alloys with equal or comparable concentrations of the three Group IV elements belong to the category of HEAs. As a result, the equimolar elements of Si-Ge-Sn alloys likely cause their atomic structures to exhibit the same core effects of metallic HEAs such as lattice distortion. Here we apply density functional theory (DFT) calculations to show that the SiGeSn HEA indeed exhibits a large local distortion effect. Unlike metallic HEAs, our Monte Carlo and DFT calculations show that the SiGeSn HEA exhibits no chemical short-range order due to the similar electronegativity of the constituent elements, thereby increasing the configurational entropy of the SiGeSn HEA. Hybrid density functional calculations show that the SiGeSn HEA remains semiconducting with a band gap of 0.38 eV, promising for economical and compatible mid-infrared optoelectronics applications. We then study the energetics of neutral single Si, Ge, and Sn vacancies and (expectedly) find wide distributions of vacancy formation energies, similar to those found in metallic HEAs. However, we also find anomalously small lower bounds (e.g., 0.04 eV for a Si vacancy) in the energy distributions, which arise from the bond reformation near the vacancy. Such small vacancy formation energies and their associated bond reformations retain the semiconducting behavior of the SiGeSn HEA, which may be a signature feature of a semiconducting HEA that differentiates from metallic HEAs.

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“…Extensive efforts have been undertaken to strengthen single-phase fcc HEAs; these include: Carbon-and Boron-doping strategies [8,17], introducing coherent precipitates [13] and introducing brittle intermetallic [7] into the fcc matrix, as well as various grain refinement strategies [18]. With the exception of the grain refinement approach, other strategies invariably lead to alloys that are not single-phase fcc, thereby leading to complex HEA matrices.…”

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confidence: 99%

“…In order to provide insight into the mechanical behaviour of the HS single-phase fcc Fe 29 Ni 29 Co 28 Cu 7 Ti 7 HEA, the yield strength versus failure strain and the ultimate tensile strength versus failure strain are plotted in Figure 5 alongside other single-phase fcc HEAs/MEAs and enhanced fcc HEAs/MEAs [7][8][9]11,13,16,17,19,27,28]. It is worth mentioning that the enhanced fcc HEAs/MEAs refer to the alloys using C- [17] and B-doping [8], coherent precipitation strengthening [9,13,28] and brittle intermetallic strengthening [7], as well as grain refinement strategies [19], to strengthen a fcc HEA/MEA matrix. As shown in Figure 5(a), the yield strength of the HS Fe 29 Ni 29 Co 28 Cu 7 Ti 7 HEA, which is comparable with those of some enhanced fcc HEAs/MEAs, is much higher than those of the single-phase fcc HEAs/MEAs.…”

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confidence: 99%

Engineering heterostructured grains to enhance strength in a single-phase high-entropy alloy with maintained ductility

MacDonald

et al. 2018

Materials Research Letters

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Coarse-grained (CG) single-phase face-centered cubic (fcc) high-entropy alloys (HEAs) normally show insufficient room temperature strength. Here we design and implement a heterogeneous grain structure to strengthen a single-phase fcc Fe 29 Ni 29 Co 28 Cu 7 Ti 7 HEA. Significantly, the heterostructured (HS) fcc HEA shows a dramatic enhancement (increasing from ∼ 350 to ∼ 614 MPa) in tensile yield strength as compared to its CG counterpart. As a result of its extraordinary work-hardening ability arising from the heterogeneous grain structure, the novel HS HEA exhibits a very high ultimate strength of ∼ 1308 MPa, and a good ductility of ∼ 23.1% which is almost identical to that of its CG counterpart. IMPACT STATEMENTIntroducing a heterogeneous grain structure to a soft fcc Fe 29 Ni 29 Co 28 Cu 7 Ti 7 HEA, the heterostructured HEA shows significantly enhanced strengths at an essentially identical ductility as compared to the CG counterpart. ARTICLE HISTORY

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Heavy carbon alloyed FCC-structured high entropy alloy with excellent combination of strength and ductility

Cited by 172 publications

References 23 publications

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

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

Semiconducting SiGeSn high-entropy alloy: A density functional theory study

Engineering heterostructured grains to enhance strength in a single-phase high-entropy alloy with maintained ductility

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