Assessment of Co-Cr-Ni ternary system by CALPHAD technique

Yang, Shuyu; Jiang, Min; Li, Hongxiao; Liu, Yang; Wang, Lei

doi:10.1007/s12598-012-0466-y

Cited by 39 publications

(13 citation statements)

References 11 publications

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“…Positive formation energy implies a tendency to phase separation at low temperature, but for this small sample size MC is not an adequate technique to explore this phase boundary. The experimental phase diagram at 800°C for the ternary NiCrCo alloy suggests that at the equimolar ratio the system forms an FCC solid solution [5]. We note that the presence of SRO may influence the location of phase boundaries, because of the lower formation energy and configurational entropy.…”

Section: Ternary Nicrcomentioning

confidence: 78%

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Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

et al. 2015

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Keywords:High entropy alloy Density functional theory Monte Carlo Short-range order Ni based alloys a b s t r a c t The aim of this study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. According to our study, the salient features for the ternary alloy are a negative SRO parameter between Ni-Cr and a positive between CrCr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni-Cr and Ni-Fe pairs and positive for Cr-Cr and Fe-Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. The predicted SRO has an impact on point-defect energetics, electron-phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys.

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Section: Ternary Nicrcomentioning

confidence: 78%

“…This simplifying assumption is due to the lack of experimental data as is the case for NiCrCo ternary [5] or NiCrCoFe quaternary alloys. Experimental phase diagram determinations show that the equimolar NiCrCo alloy is a solid solution in FCC phase [6][7][8], but no information on the detailed ordering of atoms is available.…”

Section: Introductionmentioning

confidence: 99%

Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

et al. 2015

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“…In binary Ni-Cr alloys, high Cr concentration promotes the formation of intermetallic σ and body-centered cubic (bcc) phases [46]. For the ternary Cr-Co-Ni alloys, the equilibrium phase diagram shows that Cr-Co-Ni solid solutions are in the fcc structure for the whole composition range studied here at temperatures higher than 1027K [25]. The intermetallic σ phase may occur for Cr concentration larger than 50 at.% at high temperatures.…”

Section: Phase Stabilitymentioning

confidence: 79%

“…Besides the effort of studying local chemical effect on the SFE and its influence on the deformation mechanisms, there are a lot of activities focusing on developing non-equimolar HEAs [9,12,24]. In the CrCoNi-based system, alloys composition may change from the Co-based alloys to Ni-based alloys, while keeping random solid solution with the fcc (and/or hcp) structures [25]. Already in this simple ternary case, there are nearly infinite ways to tune the composition, but a quantitative parameter to guide alloy design is still missing.…”

Section: Introductionmentioning

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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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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“…Yang et al [38] modeled the Co-Cr-Ni ternary using binary descriptions different from those implemented here as well as superfluous ternary interaction parameters. Here, the system is remodeled using the following binary models due to ternary compatibility with the Al-Co-Cr, Al-Co-Ni and Al-Cr-Ni systems: Co-Cr by Kusoffsky et al [13], Co-Ni by Guillermet F. [16], and Cr-Ni by Lee B.-J.…”

Section: Co-cr-nimentioning

confidence: 99%

Thermodynamic modeling of Al–Co–Cr, Al–Co–Ni, Co–Cr–Ni ternary systems towards a description for Al–Co–Cr–Ni

Liu

Lindwall

Gheno

et al. 2016

Calphad

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the modeling of the subsystems, especially Al-Co-Ni and Co-Cr-Ni, necessary in building a coherent Al-Co-Cr-Ni quaternary description. Some modifications are made in the description of the Al-Co-Cr [5] system and are discussed in detail later in the manuscript. The quaternary Al-Co-Cr-Ni system is studied in a separate publication [8].While B2 (β, , simple cubic type) and fcc-A1 (γ, , disordered f.c.c.) are the desired phases in MCrAlY coatings, all other phases must be modeled to give an accurate overall description of phase stability in the system. These include bcc-A2 (α, , disordered b.c.c.), 3 Pm m 3 Fm m 3 Im m 3 hcp-A3 (ε, , disordered h.c.p.), L1 2 (γ', , simple cubic type), sigma (σ, , Frank-Kasper, Figure 1 (a)) and the binary intermetallics. The present paper focuses on evaluating and modeling the important ternary alloy systems found in the Al-Co-Cr-Ni quaternary in order to produce meaningful extrapolations without the need of excessive higher order parameters. First-principles calculations based on density functional theory (DFT) are performed to supplement the lack of experimentally measured thermochemical data. By effectively combining these results with experimental information from the literature, energetically accurate parameters in the lower order systems are evaluated. Ultimately, this model will be used in the construction of a multicomponent Al-Co-Cr-Ni database in future work. 2 Literature review 2.1 Binary models used in the present workThe assessment of the Al-Co binary by Dupin and Ansara [9] reproduces all experimental results available in the literature satisfactorily and is hence adopted in the present work. The model for B2 in the original Al-Co binary was asymmetrical and was changed to the orderdisorder model by Liu et al. in previous work on the system [5], which is adopted here. The Al-Cr assessment by Saunders, which can be found in the COST507 [10] database, is also accepted without modification. The assessment for the Al-Ni binary by Ansara et al. [11], (later modified by Dupin et al. [6]) has been used extensively previously and is, therefore, adopted in the present work. There are two descriptions of the Co-Cr binary available which both reproduce certain experiments well, one by Oikawa et al. [12] and another by Kusoffsky et al. [13]. However, it 3 6/ P mmc 3 Pm m 2 4/ P mnm 4 has been found that the Oikawa description has σ end-member energies which disagree with experiments by Downie and Arslan [14] though it was adopted in the previous modeling of Al-Co-Cr [5]. It is important to have correct energies in the binary subsystems to produce accurate extrapolations to the higher order systems and for this reason, the model by Kusoffsky et al. [13] is used here. The Co-Ni and Cr-Ni binary descriptions are taken from SGTE [15], based on works by Guillermet [16] and Lee [17], respectively. In addition, the present Cr-Ni description includes a metastable description of σ following the work by Gustafson [18] in the ternary Ni-Cr-W system which is later modified by Kattner [7]. Re...

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Assessment of Co-Cr-Ni ternary system by CALPHAD technique

Cited by 39 publications

References 11 publications

Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

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

Thermodynamic modeling of Al–Co–Cr, Al–Co–Ni, Co–Cr–Ni ternary systems towards a description for Al–Co–Cr–Ni

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