Atomic-scale pathway of early-stage precipitation in Al–Mg–Si alloys

Fallah, Vahid; Korinek, Andreas; Ofori-Opoku, Nana; Raeisinia, Babak; Gallerneault, M.; Provatas, Nikolas; Esmaeili, Shahrzad

doi:10.1016/j.actamat.2014.09.004

Cited by 99 publications

(27 citation statements)

References 49 publications

(141 reference statements)

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“…Although it is evident that detailed insight into precipitation processes in Al alloys on an atomistic scale ultimately requires more advanced models (see, e.g., Refs. [10][11][12][13]), the application of simple models, like JMAK, allows a direct and analytical fit to experimental data.…”

Section: Introductionmentioning

confidence: 99%

High-precision isothermal dilatometry as tool for quantitative analysis of precipitation kinetics: case study of dilute Al alloy

et al. 2018

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An in-depth case study of precipitation kinetics for alloys is presented utilizing recent progress in high-precision isothermal dilatometry by measuring relative length changes down to the range of 10 À5 and covering large timescales exceeding 10 5 s. Using a dilute Al-Mg-Si alloy as model system, the different phases that form during isothermal heat treatment could quantitatively be analyzed both with respect to the absolute amount of precipitates and with respect to the underlying kinetics. Owing to the distinct length change features upon multi-step precipitation processes, the formation of the metastable b 00 -and b 0 -phases can unambigously be detected and furthermore can specifically be distinguished and resolved. From the reaction rate analysis of the precipitationinduced relative length change, that was isothermally measured for temperatures between 170 C and 260 C, the evolution with time of the atomic fraction of both the b 00 -and the b 0 -phase was determined. The results were also used to construct the isothermal time-temperature-precipitation diagrams which are important for technologically relevant processes.

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Section: Introductionmentioning

confidence: 99%

High-precision isothermal dilatometry as tool for quantitative analysis of precipitation kinetics: case study of dilute Al alloy

et al. 2018

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“…Eshelby's approach was generalized for anisotropic materials by Mura [12] and by Khachaturyan [13], who applied Fourier transform to express the Green function. Many applications of these fundamental works appear in the metallurgical literature [14][15][16][17]. Coherent precipitates interact with dislocations by their far field stresses (Additional stress increments depend on the size of the precipitates.…”

Section: Introductionmentioning

confidence: 99%

Elastic consideration of the precipitation in model alloys of maraging steels: theory and experimental validation

Shmulevitsh

Meshi

Pinkas³

et al. 2015

J Mater Sci

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The unique combination of high strength and high fracture toughness in maraging steels is attributed to the precipitation of mainly two phases, Ni 3 Mo and Ni 3 Ti, in the soft bcc martensitic matrix. Experimentally, it is difficult to distinguish between these phases; moreover, the effect of each precipitating phase on the properties of the steel is ambiguous. In the present work, we tackle these questions by analyzing the elastic fields and elastic energy associated with each precipitating phase and their role in the determination of the shape and relative arrangement. Using a semi-analytic approach based on the solution of the equations of elasticity by Fourier transform, the elastic fields and elastic energy associated with each precipitate were calculated. The calculations show that the minimum self-energy of both precipitates is accomplished when the smallest crystallographic misfit lies parallel to the longest geometric axis. The combination of elastic energy and surface energy provides an explanation to the observed morphologies of the precipitates, each type having an elongated shape but with a different aspect ratio. According to the calculations, the minimum self-elastic energy associated with Ni 3 Ti coherent precipitate is 2.8-fold larger than the energy of Ni 3 Mo. This implies for a larger strengthening effect of the former, as was confirmed experimentally in model alloys, one without Mo and the other without Ti. The elastic model also predicts that elongated shape and the anisotropic misfit strains favor several vertical arrangements of both precipitates, as was also verified experimentally by transmission electron microscopy of aged model alloys.

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“…Aluminium-magnesium-silicon alloys have shown considerable promise as the universal candidate materials for automotive and aerospace applications because of the formation of a Mg 2 Si heterogeneous nucleus [1,2]. Computational simulations and experimental reports have elucidated the potency of Mg 2 Si as a heterogeneous particle to reinforce α-Al and α-Mg nucleation in aluminium and magnesium alloys, respectively [3][4][5]. Although the Mg 2 Si compound has a high hardness and elastic modulus, the coarse primary Mg 2 Si phase, that has also been called Chinese script Mg 2 Si in the existing literature, that appears in the Mg-Si alloy cannot meet the requirements of engineering performance [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Mg3Sb2/Mg2Si Heterogeneous Nucleation Interface Using Density Functional Theory

Wang

Zhang

et al. 2020

Materials

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In this study, the cohesive energy, interfacial energy, electronic structure, and bonding of Mg2Si (111)/Mg3Sb2 (0001) were investigated by using the first-principles method based on density functional theory. Meanwhile, the mechanism of the Mg3Sb2 heterogeneous nucleation potency on Mg2Si grains was revealed. The results indicated that the Mg3Sb2 (0001) slab and the Mg2Si (111) slab achieved bulk-like characteristics when the atomic layers N ≥ 11, and the work of adhesion of the hollow-site (HCP) stacking structure (the interfacial Sb atom located on top of the Si atom in the second layer of Mg2Si) was larger than that of the other stacking structures. For the four HCP stacking structures, the Sb-terminated Mg3Sb2/Si-terminated Mg2Si interface with a hollow site showed the largest work of adhesion and the smallest interfacial energy, which implied the strongest stability among 12 different interface models. In addition, the difference in the charge density and the partial density of states indicated that the electronic structure of the Si-HCP-Sb interface presented a strong covalent, and the bonding of the Si-HCP-Mg interface and the Mg-HCP-Sb interface was a mixture of a covalent bond and a metallic bond, while the Mg-HCP-Mg interfacial bonding corresponded to metallicity. As a result, the Mg2Si was conducive to form a nucleus on the Sb-terminated-hollow-site Mg3Sb2 (0001) surface, and the Mg3Sb2 particles promoted the Mg2Si heterogeneous nucleation, which was consistent with the experimental expectations.

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Atomic-scale pathway of early-stage precipitation in Al–Mg–Si alloys

Cited by 99 publications

References 49 publications

High-precision isothermal dilatometry as tool for quantitative analysis of precipitation kinetics: case study of dilute Al alloy

High-precision isothermal dilatometry as tool for quantitative analysis of precipitation kinetics: case study of dilute Al alloy

Elastic consideration of the precipitation in model alloys of maraging steels: theory and experimental validation

Investigation on Mg3Sb2/Mg2Si Heterogeneous Nucleation Interface Using Density Functional Theory

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