Cluster-plus-glue-atom model and universal composition formulas [cluster](glue atom)x for BCC solid solution alloys

Wang

et al. 2020

Sci Rep

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The present work investigated the composition evolution of the TMS series of Ni-base single crystal (SC) superalloys in light of the cluster formula approach systematically. The cluster formula of SC superalloys could be expressed with $${[}\overline{{{\text{Al}}}} {-} \overline{{{\text{Ni}}}} 12{](}\overline{{{\text{Al}}}} {, }\overline{{{\text{Cr}}}} {)}m$$ [ Al ¯ - Ni ¯ 12 ] ( Al ¯ , Cr ¯ ) m , in which all the alloying elements were classified into three groups, Al series ($$\overline{{{\text{Al}}}}$$ Al ¯ ), Cr series ($$\overline{{{\text{Cr}}}}$$ Cr ¯ ), and Ni series ($$\overline{{{\text{Ni}}}}$$ Ni ¯ ). It was found that the total atom number (Z) of the cluster formula units for TMS series of superalloys varies from Z ~ 17 to Z ~ 15.5, and then to Z ~ 16 with the alloy development from the 1st to the 6th generation, in which the superalloys with prominent creep resistance possess an ideal cluster formula of $${[}\overline{{{\text{Al}}}} {-} \overline{{{\text{Ni}}}} 12{](}\overline{{{\text{Al}}}} 1.5\overline{{{\text{Cr}}}} 1.5{)}$$ [ Al ¯ - Ni ¯ 12 ] ( Al ¯ 1.5 Cr ¯ 1.5 ) with Z = 16. Similar tendency of composition evolution also appears in the PWA and CMSX series of SC superalloys. Typical TMS series of superalloys with prominent creep properties generally exhibit a moderate lattice misfit of γ/γ′ which could render alloys with appropriate particle size of cuboidal γ′ precipitates to acquire a maximum strength increment by precipitation strengthening mechanism. More importantly, the relationship between the lattice misfit (δ) of γ/γ′ and the creep rupture lifetime (tr) of superalloys was then established, showing a linear correlation in the form of lgtr–lg|δ|3/2 at both conditions of 900 °C/392 MPa and 1100 °C/137 MPa. Combined with the lattice misfit, the cluster formula approach would provide a new way to modify or optimize the compositions of Ni-base superalloys for further improvement of creep property.

Section: Composition Rules Of Ni-base Sc Superalloys Via the Cluster mentioning

confidence: 99%

Section: Composition Rules Of Ni-base Sc Superalloys Via the Cluster mentioning

confidence: 99%

Composition rules of Ni-base single crystal superalloys and its influence on creep properties via a cluster formula approach

Wang

et al. 2020

Sci Rep

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“…Furthermore, the Mo eq describes the β structural stability of Ti alloys alone, and could not correlate directly with the properties, such as the Young's modulus. Actually, the interactions among alloying elements with the base element could be incarnated into the CSROs of solid solutions, which is the significant microstructural feature [15][16][17] . Based on CSROs, we proposed a 'cluster-plus-glue-atom' structural model to describe the local atomic distribution of alloying solute elements.…”

Section: Characteristic Parameters In Low-e β-Ti Alloysmentioning

confidence: 99%

“…Besides Mo eq , the d-electron theory method 10,11 and valence electron concentration [12][13][14] are frequently used to design multicomponent low-E alloys. A cluster-formula approach is also applied to design alloy compositions in multicomponent systems, which considers the correlations among alloying solute elements and the base element in light of the chemical short-range orders (CSROs) of solid solutions and then gives chemical compositions intuitively [15][16][17] . Thus, a series of low-E β-Ti alloys have been achieved by the cluster formula of [(Mo,Sn) − (Ti,Zr) 14 ](Nb,Ta) 1-3 , in which the lowest E = 48 GPa could reach at the [(Mo 0.5 Sn 0.5 ) − (Ti 13 18 .…”

Section: Introductionmentioning

confidence: 99%

Cluster-formula-embedded machine learning for design of multicomponent β-Ti alloys with low Young’s modulus

Yang

Wang

et al. 2020

npj Comput Mater

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The present work formulated a materials design approach, a cluster-formula-embedded machine learning (ML) model, to search for body-centered-cubic (BCC) β-Ti alloys with low Young's modulus (E) in the Ti-Mo-Nb-Zr-Sn-Ta system. The characteristic parameters, including the Mo equivalence and the cluster-formula approach, are implemented into the ML to ensure the accuracy of prediction, in which the former parameter represents the BCC-β structural stability, and the latter reflects the interactions among elements expressed with a composition formula. Both auxiliary gradient-boosting regression tree and genetic algorithm methods were adopted to deal with the optimization problem in the ML model. This cluster-formula-embedded ML can not only predict alloy property in the forward design, but also design and optimize alloy compositions with desired properties in multicomponent systems efficiently and accurately. By setting different objective functions, several new β-Ti alloys with either the lowest E (E = 48 GPa) or a specific E (E = 55 and 60 GPa) were predicted by ML and then validated by a series of experiments, including the microstructural characterization and mechanical measurements. It could be found that the experimentally obtained E of predicted alloys by ML could reach the desired objective E, which indicates that the cluster-formula-embedded ML model can make the prediction and optimization of composition and property more accurate, effective, and controllable.

“…[33][34][35][36] In addition, cuboidal L2 1 nanoparticles were also precipitated in a newly designed light-weight BCC-based Al 1.5 CrFeMnTi HEA, which exhibits a high microstructural stability. 37 In our recent work, we designed a series of HEAs 23,38 with a composition of Al 2 M 14 (M represents different combinations of Ni, Co, Fe, and Cr) with the guide of the cluster formula approach, 39 in which the cuboidal B2 nanoparticles are found to be precipitated coherently into the BCC matrix. 23,38 Among them, the typical BCC Al 0.7 NiCoFeCr 2 HEA, derived from the composition of Al 2 M 14 with M 5 Ni 1 Co 1 Fe 1 Cr 2 , exhibits a higher yield strength of above 1700 MPa due to the special coherent microstructure.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ti substitution for Al on the cuboidal nanoprecipitates in Al_0.7NiCoFeCr₂ high-entropy alloys

Hao

et al. 2018

J. Mater. Res.

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