Scheil ternary projection (STeP) diagrams for designing additively manufactured functionally graded metals

Moustafa, Abdel R.; Durga, A.; Lindwall, Greta; Cordero, Zachary C.

doi:10.1016/j.addma.2019.101008

Cited by 10 publications

(11 citation statements)

References 46 publications

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“…More recently, investigators have utilized the CALculation of PHAse (CALPHAD) diagram computations to predict the formation of brittle phases and possible crack susceptibility in complex Ni-base superalloy systems. [28][29][30] Without a doubt, these computational tools are powerful methods that can utilize Scheil solidification modeling to predict cracking susceptibility of alloy systems, both simple and complex. However, the goal of this work was to demonstrate the effectiveness of the simple model, under the original constraints of the Scheil equation.…”

Section: Cracking Susceptibility and Effect Of Diffusionmentioning

confidence: 99%

Effects of Alloy Composition and Solid-State Diffusion Kinetics on Powder Bed Fusion Cracking Susceptibility

Hyer

Zhou

Mehta

et al. 2020

J. Phase Equilib. Diffus.

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Laser powder bed fusion (LPBF) has demonstrated its unique ability to produce customized, complex engineering components. However, processing of many commercial Al-alloys by LPBF remains challenging due to the formation of solidification cracking, although they are labelled castable or weldable. In order to elucidate this divergence, solidification cracking susceptibility from the steepness of the solidification curves, specifically |dT/df S 1/2 |, as the fraction solidified nears 1 towards complete solidification, was calculated via Scheil-Gulliver model as a function of solute concentration in simple binary Al-Si, Al-Mg, and Al-Cu systems. Introduction of ''diffusion in solid'' into Scheil-Gulliver model resulted in a drastic reduction in the cracking susceptibility (i.e., reduction in the magnitude of |dT/df S 1/2 |) and a shift in the maximum |dT/df S 1/2 | to higher concentrations of solute. Overall, the calculated solidification cracking susceptibility correlated well with experimental observation made using LPBF AA5083 (e.g., Al-Mg) and Al-Si binary alloys with varying Si concentration. Cracking susceptibility was found to be highly sensitive to the composition of the alloy, which governs the variation of |dT/df S 1/2 |. Furthermore, experimental observation suggests that the contribution of ''diffusion in solids'' to reduce the cracking susceptibility can be more significant than what is expected from an instinctive assumption of negligible diffusion and rapid cooling typically associated with LPBF.

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Section: Cracking Susceptibility and Effect Of Diffusionmentioning

confidence: 99%

Effects of Alloy Composition and Solid-State Diffusion Kinetics on Powder Bed Fusion Cracking Susceptibility

Hyer

Zhou

Mehta

et al. 2020

J. Phase Equilib. Diffus.

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“…With the aid of the CALPHAD technique, carbon chemical potentials and martensite transformation temperature for FGMs can be calculated using the General Steel database in JMatPro V8 software, taking the chemical composition as the input. Moustafa et al [ 81 ] developed new non‐equilibrium phase diagrams, so‐called Scheil Ternary Projection diagrams, to optimize the design of Fe‐Cr‐Al ternary FGMs. Preliminary results revealed that intermetallic phase fields expanded dramatically through rapid solidification during the AM process.…”

Section: Design Concepts For Fgmammentioning

confidence: 99%

A Review on Functionally Graded Materials and Structures via Additive Manufacturing: From Multi‐Scale Design to Versatile Functional Properties

Yan

Feng

Liu

et al. 2020

Adv Materials Technologies

315

116

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Functionally graded materials (FGMs) and functionally graded structures (FGSs) are special types of advanced composites with peculiar features and advantages. This article reviews the design criteria of functionally graded additive manufacturing (FGAM), which is capable of fabricating gradient components with versatile functional properties. Conventional geometrical‐based design concepts have limited potential for FGAM and multi‐scale design concepts (from geometrical patterning to microstructural design) are needed to develop gradient components with specific graded properties at different locations. FGMs and FGSs are of great interest to a larger range of industrial sectors and applications including aerospace, automotive, biomedical implants, optoelectronic devices, energy absorbing structures, geological models, and heat exchangers. This review presents an overview of various fabrication ideas and suggestions for future research in terms of design and creation of FGMs and FGSs, benefiting a wide variety of scientific fields.

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“…In addition to thermodynamic driving force, we can also use the non-equilibrium phase diagram, predicted by the Scheil-Gulliver simulations 47,48 (see its definition in the Introduction section), to predict the formation of IMCs in fast cooling processes, such as the AM process 49,50 . Here, we used the PyCalphad software 50,87 to calculate this non-equilibrium phase diagram with the thermodynamic description modelled by Sundman et al 9 .…”

Section: Formation Of Non-equilibrium Imcs Through Thermodynamic Analysismentioning

confidence: 99%

“…Phase diagram, as the beginning of wisdom to guide any work in materials science and engineering 46 , is the most used tool to analyze equilibrium IMCs under a given temperature and composition (usually under external pressure P = 0 GPa). Additionally, non-equilibrium simulations in terms of the Scheil-Gulliver model 47,48 can be used to analyze the forming IMCs in fast cooling processes by assuming that no diffusion takes place in the solid and that solute redistribution in the liquid is infinitely fast [49][50][51] . The Scheil simulations have been used to, for example, design optimal composition for additively manufactured functionally graded metals 49,50 and predict liquidus and solidus temperatures of steel 51 .…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, non-equilibrium simulations in terms of the Scheil-Gulliver model 47,48 can be used to analyze the forming IMCs in fast cooling processes by assuming that no diffusion takes place in the solid and that solute redistribution in the liquid is infinitely fast [49][50][51] . The Scheil simulations have been used to, for example, design optimal composition for additively manufactured functionally graded metals 49,50 and predict liquidus and solidus temperatures of steel 51 . In addition to phase diagram, non-equilibrium IMCs can be predicted by calculating thermodynamic driving forces for the phases of interest with respect to supercooled liquid and associated solid phases; see the predicted interface phases at the Cu/solder joints by Lee et al 52 .…”

Section: Introductionmentioning

confidence: 99%

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Forming Mechanism of Equilibrium and Non-equilibrium Metallurgical Phases in Dissimilar Materials: Illustrated With Aluminum/steel (Al-Fe) Joints

Shang

Sun

Pan

et al. 2021

Preprint

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Forming metallurgical phases has a critical impact on the performance of dissimilar materials joints. Here, we shed light on the forming mechanism of equilibrium and non-equilibrium intermetallic compounds (IMCs) in the dissimilar aluminum/steel joints with respect to processing history (e.g., the pressure- and temperature-profiles) and chemical composition, where the used knowledge of free energy and atomic diffusion in the Al-Fe system was taken from first-principles phonon calculations and data available in the literature. We found that the metastable while ductile (judged by the presently predicted elastic constants) Al6Fe is a pressure (P) favored IMC observed in the processes involving high pressures. The MoSi2-type Al2Fe is a brittle and a strong P-favored IMC observed at high pressures. The stable, brittle h-Al5Fe2 is the most commonly observed IMC (followed by q-Al13Fe4) in almost all processes, such as fusion/solid-state welding and additive manufacturing (AM), since h-Al5Fe2 is temperature-favored, possessing high thermodynamic driving force of formation and the fastest atomic diffusivity among all Al-Fe IMCs. Notably the ductile AlFe3, the less ductile AlFe, and most of the other IMCs can be formed during AM, making AM a superior process to achieve desired IMCs in dissimilar materials. In addition, the unknown configurations of Al2Fe and Al5Fe2 were also examined by machine learning based datamining together with first-principles verifications and structure predictor. All the IMCs, which are not P-favored, can be identified using the conventional equilibrium phase diagram and the Scheil-Gulliver non-equilibrium simulations.

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Scheil ternary projection (STeP) diagrams for designing additively manufactured functionally graded metals

Cited by 10 publications

References 46 publications

Effects of Alloy Composition and Solid-State Diffusion Kinetics on Powder Bed Fusion Cracking Susceptibility

Effects of Alloy Composition and Solid-State Diffusion Kinetics on Powder Bed Fusion Cracking Susceptibility

A Review on Functionally Graded Materials and Structures via Additive Manufacturing: From Multi‐Scale Design to Versatile Functional Properties

Forming Mechanism of Equilibrium and Non-equilibrium Metallurgical Phases in Dissimilar Materials: Illustrated With Aluminum/steel (Al-Fe) Joints

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