Article
Chemistry, Physical
Tsai-Fu Chung, Shan-Qiao Lin, Hongxing Li, Chien-Nan Hsiao, Jer-Ren Yang, Cheng-Si Tsao, Takahito Ohmura
Summary: We present a study on the microstructure evolution and strengthening behavior of delta'/theta'/delta' precipitates in the aged Al-Cu-Li-Mg aluminum alloy using atomic high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and in-situ TEM compression straining. The in-situ microstructure evolution of the delta'/theta'/delta' precipitates is observed through atomic HAADF-STEM images. The formation of a monolayer GP(theta') zone, grown on the (001)(Al) plane, and subsequent transformation to theta' phase leads to the maturity of delta'/theta'/delta' precipitates. Dislocation-precipitate interactions, as well as the effects of inclined boundaries and thin T-1 precipitates, are investigated during in-situ TEM compression straining. The presence of stacking fault layers within sheared delta'/theta'/delta' precipitates is revealed by atomic HAADF-STEM images. Copyright © 2023 Elsevier B.V. All rights reserved.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Tsai-Fu Chung, Yo-Lun Yang, Cheng-Ling Tai, Makoto Shiojiri, Chien-Nan Hsiao, Cheng-Si Tsao, Wei-Chih Li, Zhusheng Shi, Jianguo Lin, Hsueh-Ren Chena, Jer-Ren Yang
Summary: High-resolution HAADF-STEM analysis revealed atomic lattice defects in various types of eta precipitates in an Al-Zn-Mg-Cu alloy undergoing creep-age forming treatment. These defects, including elongated hexagonal lattice defects labeled as Type I and Type II, are associated with lattice accommodation during the forming process. The presence of complex defects like Penrose tiling defect and entirely-passed faulted layers also influences the morphology and growth direction of the precipitates. Furthermore, Zn/Cu diffusion from the matrix to the precipitate along specific planes was observed in the atomic STEM image.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Timothy G. Lach, David A. Collins, Thak Sang Byun
Summary: Thermal aging of ferrite in duplex stainless steels leads to a complex microstructural evolution that can cause significant changes in mechanical properties. The addition of a modest amount of Mo accelerates spinodal decomposition and precipitation events, but also results in the formation of a separate Mo-rich phase, affecting fracture and impact toughness of the material.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Engineering, Manufacturing
Xiao Yang, Qunli Zhang, Yang Zheng, Xiaochuan Liu, Denis Politis, Omer El Fakir, Liliang Wang
Summary: The lubricant behavior at elevated temperatures was investigated through pin-on-disc tests between P20 tool steel and AA7075 aluminum alloy. The evolution of the coefficient of friction (COF) was observed to consist of three distinct stages with different friction mechanisms, influenced by temperature, contact pressure, and sliding speed. In the final stage, lubricant breakdown occurred due to increased temperature, contact pressure, sliding speed, and decreased initial lubricant volume, leading to high friction values at the interface.
INTERNATIONAL JOURNAL OF EXTREME MANUFACTURING
(2021)
Article
Engineering, Manufacturing
Swarit Anand Singh, Satwik Priyadarshi, Puneet Tandon
Summary: The study investigates suitable tool materials and lubricants for Elevated Temperature Incremental Forming of Aluminium alloy, evaluating different options through experiments. The findings suggest that Tool steel (EN-31) and Molybdenum disulfide mixture are the most appropriate tool material and lubricant, respectively.
INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING
(2021)
Article
Materials Science, Multidisciplinary
Chao Jiang, Isabella J. van Rooyen, Subhashish Meher
COMPUTATIONAL MATERIALS SCIENCE
(2020)
Article
Materials Science, Multidisciplinary
Sandeep Sugathan, Saswata Bhattacharya
COMPUTATIONAL MATERIALS SCIENCE
(2020)
Article
Crystallography
Sanket Sarkar, Yan Gao, Shenyan Huang, Saswata Bhattacharya, Swapnil Patil, Ramkumar Oruganti
Article
Engineering, Multidisciplinary
P. Kasirajan, S. Bhattacharya, A. Rajagopal, J. N. Reddy
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2020)
Article
Materials Science, Multidisciplinary
Tushar Jogi, Saswata Bhattacharya
Summary: Ni-base superalloys exhibit an intricate network of dislocations around gamma ' precipitates during high-temperature low-to-intermediate stress creep. Three-dimensional discrete dislocation dynamics simulations reveal the evolution of dislocation network on the surfaces of unsheared, cuboidal gamma ' precipitates. The study suggests that dislocation climb is the rate-controlling mechanism, with a constant mobile-to-immobile dislocation density ratio observed at steady state.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2021)
Article
Nanoscience & Nanotechnology
M. Verma, S. Sugathan, S. Bhattacharya, R. Mukherjee
Summary: In polycrystalline thin films, the universal behavior of mobile thermal grooves is independent of film thickness, surface diffusivity, and grain boundary mobility when the grain boundary motion is in a steady state. The onset of universality of surface profiles occurs simultaneously with the attainment of steady-state motion of the grain boundary and a constant value of groove depth.
SCRIPTA MATERIALIA
(2022)
Article
Nanoscience & Nanotechnology
Hemanth Kumar, Anuj Dash, Aloke Paul, Saswata Bhattacharyya
Summary: This study estimates the composition-dependent pseudo-binary interdiffusion coefficients and the main intrinsic diffusion coefficients of the NiCoFeCr system using the PB diffusion couple method. The diffusion parameters are optimized using a physics-informed machine learning inverse method. The results demonstrate the importance of estimating intrinsic diffusion coefficients and their role in generating a reliable mobility database.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
P. Pankaj, Saswata Bhattacharyya, Subhradeep Chatterjee
Summary: Bimetallic nanoparticles exhibit diverse morphologies, and their development is influenced by spinodal decomposition and wetting behavior. Confined spinodal decomposition leads to the formation of compositionally modulated rings on the surface of the nanoparticles, which eventually coarsen and break down to form core-shell or Janus structures. The final morphology depends on the contact angle and particle size.
Article
Physics, Applied
Pravallika Bandaru, Saswata Bhattacharyya, Shourya Dutta-Gupta
Summary: Surface plasmon polaritons (SPPs) supported by an Ag-Cu alloy film with spinodal decomposition exhibit far-field response controlled by alloy composition and near-fields strongly dependent on film microstructure and composition. Inhomogeneous fields are a result of constructive and destructive interference of SPPs. Enhancement of spin angular momentum components in phase-separated alloy films opens up possibilities for applications in sensing, nanomanipulation, and light modulation.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
P. Pankaj, S. Bhattacharyya, S. Chatterjee
Summary: An embedded-domain phase-field formalism is used to study phase transformation pathways in bimetallic nanoparticles. The competition and interaction between bulk and surface-directed spinodal decomposition processes, as well as the role of capillarity, are identified as the main factors determining BNP morphology. By examining the ratio of bulk to capillary driving forces (Δf) and the ratio of surface energies to interfacial energy related to the contact angle (θ), different simulated morphologies and their relationship with processing parameters can be predicted.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Anuj Dash, Saswata Bhattacharyya, Aloke Paul
Summary: An innovative design strategy of creating diffusion couples is used to intersect the diffusion paths in a multi-component alloy, allowing for the experimental estimation of diffusion coefficients in a quinary system. The study shows the significant influence of the vacancy wind effect on certain diffusion coefficients.
Article
Materials Science, Multidisciplinary
Hemanth Kumar, Neelamegan Esakkiraja, Anuj Dash, Aloke Paul, Saswata Bhattacharyya
Summary: This study proposes a numerical inverse method based on physics-informed neural networks (PINN) to calculate composition-dependent diffusion coefficients in pseudo-binary (PB) diffusion couples in multicomponent alloys. The method utilizes available data and physics-based constraints to obtain optimized design parameters and exact solutions for constrained governing differential equations. The study also highlights the importance of experimentally estimated intrinsic diffusion coefficients for predicting reliable composition-dependent mobility data.
PHILOSOPHICAL MAGAZINE
(2023)
Article
Materials Science, Multidisciplinary
M. Verma, S. Sugathan, S. Bhattacharyya, R. Mukherjee
Summary: In this study, a three-dimensional phase-field model was developed to simulate concurrent capillary-driven grain growth and surface diffusion-controlled thermal grooving. By investigating the influence of film thickness and surface diffusivity on the interactions between thermal grooving and grain growth, it was found that the degree of stagnation of grain boundaries increases due to the modification of boundary curvature normal to the film surface.
Article
Chemistry, Multidisciplinary
Sandeep Sugathan, Krishnamohan Thekkepat, Soumya Bandyopadhyay, Jiyoung Kim, Pil-Ryung Cha
Summary: This study develops a computational model to simulate the switching behavior of ferroelectric hafnium zirconium oxide (HZO) thin films and introduces a novel approach to optimize the coefficients describing the free energy. The model accurately captures experimental observations and provides insights for enhancing ferroelectric properties by controlling grain morphology and crystalline texture.
