Thermodynamics and Kinetics of Alloys: Session III
Sponsored by: TMS Structural Materials Division, TMS: Alloy Phases Committee
Program Organizers: Ji-Cheng Zhao, University of Maryland; Wei Xiong, University of Pittsburgh; Chuan Zhang, CompuTherm LLC; Shuanglin Chen, CompuTherm LLC
Tuesday 8:00 AM
March 21, 2023
Room: Sapphire M
Location: Hilton
Session Chair: Qing-Qiang Ren, Oak Ridge National Laboratory; Kamalnath Kadirel, CompuTherm, LLC
8:00 AM Invited
A Quantitative Model for the Electrodeposition of Metals and Alloys Based on In Situ Characterizations: Yifan Ma1; Jakub Pepas1; Hailong Chen1; 1Georgia Institute of Technology
Electrodeposition or electroplating is a widely used method in the mining, refinery, plating and coating of metals and alloys. Historically, the receipts of electrodeposition are mostly the results of trial-and-error development. Partly because the electrodeposition process of metals and alloys is more complicated than pyrometallurgy, where many factors, such as voltage, current, electrolyte concentration, electrode surface, additives, and temperature etc., can significantly impact the phase, composition, morphology, and porosity of the deposited product. In order to develop rational design strategies for electrodeposited alloys, here we report the development of a multi-physics model that can quantitatively explain and predict the formation of metals and alloys in given deposition conditions. This model is verified by state-of-the-art in situ characterizations of the electrodeposition process, with using a few model materials systems, including copper and zinc alloys.
8:20 AM Invited
An investigation and selected applications of the effective bond energy formalism: Giancarlo Trimarchi1; Qing Chen1; 1Thermo-Calc Software AB
The recently introduced Effective Bond Energy Formalism (EBEF) models the Gibbs energy of multi-sublattice phases with a sum of terms corresponding to distinct pairs, triplets, etc, of sublattices. Density Functional Theory (DFT) is the tool of choice to generate the data needed to estimate the parameters of the model. In contrast with the Compound Energy Formalism (the standard CALPHAD approach to model multi-sublattice systems), the ternary endmembers can be estimated with the EBEF using only the DFT total energies of the binary endmembers. This affords an advantage when the number of endmembers increases rapidly with the number of sublattices like for the sigma phase. We have previously proposed to fit the EBEF coefficients to the binary DFT data by the technique of singular value decomposition. Here, we further investigate this approach applying it to the sigma-phase endmembers of a range of systems including Al-Nb-Ti, Al-Nb-V, and Co-Cr-Ta.
8:40 AM
Phase diagram determination of ternary systems for understanding the TCP phase formation in Ni-based superalloys: Chuangye Wang1; Ji-Cheng Zhao1; 1University of Maryland
Accurate predictions of the formation of the topologically close-packed (TCP) phases (σ, μ, P, and Laves) would significantly accelerate the design of both Ni-based and Co-based superalloys by reduction of both the long-term exposure experiments and the number of experimental iterations. Diffusion multiples were utilized to generate a large amount of tie-line data for the ternary systems in Co-(Cr,Ni)-(Mo,Nb,Ta,W) systems. To accelerate the electron-probe microanalysis (EPMA) data gathering process, fast digital WDS mapping was performed first to identify the key regions of interest and then detailed EPMA scans at the most critical regions were performed later. Such a combined process was found to be very effective in obtaining reliable tie-line data. The pertinent literature ternary phase diagram results were reassessed and combined with our experimental data. These data will be used for CALPHAD assessments of thermodynamic parameters of the TCP phases.
9:00 AM
First-principles Calculations and Thermodynamic Modeling of the Mg-In System with Order-disorder Transitions: Yuanchen Gao1; Bi-Cheng Zhou1; 1University of Virginia
In is an interesting alloying element in Mg because it can alter the habit plane of the nanoscale precipitates in Mg alloys. In the current work, thermodynamic modeling of the Mg-In system is performed by the CALPHAD approach in combination with available experimental data in the literature and first-principles calculations in this work. The finite-temperature thermodynamic properties of all stoichiometric phases are predicted with quasi-harmonic phonon calculations. First-principles calculations are performed on FCC, HCP, and BCT using special quasi-random structures to predict the enthalpy of mixing in the solid solution phases. A four-sublattice model is used to describe the order-disorder transitions in the FCC lattice. Besides, the ground state phases of FCC and HCP phases are searched by cluster expansion approach parameterized by first-principles calculations. The Monte Carlo simulations with Hamiltonian from the cluster expansion are performed to calculate the configurational free energies and the corresponding FCC order-disorder phase diagram.
9:20 AM Break
9:40 AM Invited
High-throughput Design of Multi-principal Element Alloys with Spinodal Decomposition Assisted Microstructures: Shalini Roy Koneru1; Kamalnath Kadirvel2; Yunzhi Wang1; 1The Ohio State University; 2CompuTherm LLC
Researchers recently observed that spinodal decomposition assisted phase transformation pathways in multi-principal element alloys (MPEAs) could generate nanoscale periodic multiphase microstructures with promising mechanical and functional properties. Thus, we recently developed a CALPHAD framework based on existing theoretical analysis of spinodal decomposition in multicomponent systems to predict the stability of solid solutions in MPEAs against spinodal decomposition. Here, we extend this framework to explore the compositional and temperature spaces and design MPEAs with novel microstructures. We illustrate our methodology through high throughput CALPHAD calculations in Fe-Co-Ni-Mn-Cu system. We present the spinodal temperature as a function of alloy composition through Morral’s constant core component diagrams and the MPEAs of interest are selected based on phase equilibrium calculations. We further calculate the initial concentration modulations (CMs) during the early stages of spinodal decomposition for selected MPEAs as their difference from the equilibrium phase compositions could be further utilized in engineering the microstructures.
10:00 AM Invited
Understanding Precipitation and Age Hardening Of FeCrAl Alloy Using Explainable Artificial Intelligence: Indranil Roy1; Subhrajit Roychowdhury1; Sandipp Krishnan Ravi1; Bojun Feng1; Rajnikant Umretiya1; Andrew Hoffman1; Raul Rebak1; 1GE Global Research
FeCrAl alloy has been historically proven to be a good oxidation-resistant material at both high and low temperatures and hence a top candidate for nuclear reactor cladding material to replace Zr-based alloys. One of the major challenges of using FeCrAl is the formation of Cr-precipitates that make the alloy brittle after exposure to high temperatures. With the age-hardening data from literature along with experiments performed at GE Research, we demonstrate a systematic data-driven modeling approach to understanding precipitation in FeCrAl alloys. Historically, it was accepted that Aluminum (Al) suppresses precipitation. But with the accumulation of a high volume of data over a larger temperature range, we discuss how Al can incite precipitation at lower temperature ranges while suppressing it at higher temperatures. Along with predictive modeling, explainable AI, which is a novel tool in material science, can help understand the competition of thermodynamics and kinetics of precipitation for FeCrAl alloy.
10:20 AM
Density-based Phase-field Modelling of the Interplay between Grain Boundary Segregation Transition and Structure: Reza Darvishi Kamachali1; Theophilus Wallis1; 1Federal Institute for Materials Research and Testing (BAM)
Grain boundary (GB) chemical and structural variations can significantly influence materials performance. The former is generally ascribed to the structural gradient between the grain and GB. While GB segregation may be accompanied by chemical and structural variations, clear insights about the GB’s thermodynamic phase behavior upon coupling between its chemistry and structure is lacking. Using the CALPHAD integrated density-based phase field model, we study the co-evolution of GB’s structure and segregation in Fe-Mn alloys. We found that the GB segregation transition is amplified if its structure can respond to chemical variation. Additionally, the coupling between GB structural and segregation evolution was found to enable co-existence of the spinodally formed low- and high-Mn phases within the GB. In the light of atomistic simulations, we expand on investigating the correlation between the parameters that characterize the GB density map with GB properties.
10:40 AM
Thermal Grooving and Grain Growth in a Polycrystalline Thin Film: A Phase-field Study: Miral Verma1; Sandeep Sugathan2; Saswata Bhattacharya3; Rajdip Mukherjee4; 1KU Luven Belgium; 2Kookmin University; 3Indian Institute of Technology Hyderabad; 4Indian Institute of Technology Kanpur
In this study, we aim to study the effect of thermal grooving on grain boundary motion and explore the effects of film thickness, surface/grain boundary energy, and surface mobility on grain growth. Towards achieving this goal, a three-dimensional phase-field model is employed that can simulate concurrent curvature-driven grain growth and surface-diffusion-controlled thermal grooving. The simulated surface profile for a bicrystal shows excellent agreement with Mullins’ classical theory of mobile grooves for any groove shape. We also report the existence of a universal behavior of a mobile thermal groove. In polycrystalline thin films, we find that with the decrease in film thickness, the degree of stagnation increases, manifested by an increase in deviation from the ideal grain growth behavior. We observe that complete stagnation of grain structure is only possible when all the grains are larger than a critical grain size that corresponds to a critical grain boundary curvature.
11:00 AM
Microstructural Design via Spinodal-mediated Phase Transformation Pathways in High-entropy Alloys (HEAs) Using Phase-field Modelling: Kamalnath Kadirvel1; Shalini Koneru1; Hamish Fraser1; Yunzhi Wang1; 1The Ohio State University
Multi-phase HEAs have exhibited superior and unprecedented properties based on the relative arrangements between the co-existing phases. It becomes crucial to identify the various parameters that influence microstructural topology. In this work, we considered a spinodal-mediated phase decomposition of single phase disordered solid solution into a mixture of ordered and disordered solid solutions. We simulated the possible microstructures using phase-field modelling by varying equilibrium volume fractions, modulus mismatch between the co-existing phases, and the free energy surfaces. We observed that topology of the free energy surface is one of the critical parameters in determining the microstructure that is ignored in the existing literature. We focus on the following morphological characteristics: bi-continuous microstructures vs. precipitates + matrix microstructures, ordered matrix + disordered precipitates vs. disordered matrix + ordered precipitates, and the discreteness of the precipitate phase. Our parametric study may help in microstructural design of multi-phase HEAs.