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Your search keyword '"Phanikumar, Gandham"' showing total 182 results
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182 results on '"Phanikumar, Gandham"'

1. MICROSIM: A high performance phase-field solver based on CPU and GPU implementations

Author

Dutta, Tanmay, Mohan, Dasari, Shenoy, Saurav, Attar, Nasir, Kalokhe, Abhikshek, Sagar, Ajay, Bhure, Swapnil, Pradhan, Swaroop . S., Praharaj, Jitendriya, Mridha, Subham, Kushwaha, Anshika, Shah, Vaishali, Gururajan, M. P., Shenoi, V. Venkatesh, Phanikumar, Gandham, Bhattacharyya, Saswata, and Choudhury, Abhik

Subjects
Condensed Matter - Materials Science, Mathematical Physics
Abstract

The phase-field method has become a useful tool for the simulation of classical metallurgical phase transformations as well as other phenomena related to materials science. The thermodynamic consistency that forms the basis of these formulations lends to its strong predictive capabilities and utility. However, a strong impediment to the usage of the method for typical applied problems of industrial and academic relevance is the significant overhead with regard to the code development and know-how required for quantitative model formulations. In this paper, we report the development of an open-source phase-field software stack that contains generic formulations for the simulation of multi-phase and multi-component phase transformations. The solvers incorporate thermodynamic coupling that allows the realization of simulations with real alloys in scenarios directly relevant to the materials industry. Further, the solvers utilize parallelization strategies using either multiple CPUs or GPUs to provide cross-platform portability and usability on available supercomputing machines. Finally, the solver stack also contains a graphical user interface to gradually introduce the usage of the software. The user interface also provides a collection of post-processing tools that allow the estimation of useful metrics related to microstructural evolution.

Published
2024

3. Interface Response Functions for multicomponent alloy solidification- An application to additive manufacturing

Author

Hariharan, V. S., Murty, B. S., and Phanikumar, Gandham

Subjects
Condensed Matter - Materials Science
Abstract

The near-rapid solidification conditions during additive manufacturing can lead to selection of non-equilibrium phases. Sharp interface models via interface response functions have been used earlier to explain the microstructure selection under such solidification conditions. However, most of the sharp interface models assume linear superposition of contributions of alloying elements without considering the non-linearity associated with the phase diagram. In this report, both planar and dendritic Calphad coupled sharp interface models have been implemented and used to explain the growth-controlled phase selection observed at high solidification velocities relevant to additive manufacturing. The implemented model predicted the growth-controlled phase selection in multicomponent alloys, which the other models with linear phase diagram could not. These models are calculated for steels and a Nickel-based superalloy and the results are compared with experimental observations., Comment: 33 pages, 11 figures, preprint

Published
2023

12. Multiscale Modeling in Arc Welding Using Secondary Thermal Cycle

Author

John, Deepu Mathew, Phanikumar, Gandham, Ramachandran, Divakar, Editorial Board Member, Basu, Bikramjit, Editorial Board Member, Chattoraj, I, Editorial Board Member, Prasad, N. Eswara, Editorial Board Member, Manna, Indranil, Editorial Board Member, Gokhale, Amol A., Editorial Board Member, Reddy, G. Madhusudan, Editorial Board Member, Shrivastava, Amber, editor, Arora, Amit, editor, Srivastava, Chandan, editor, Dhawan, Nikhil, editor, and Shekhar Singh, Sudhanshu, editor

Published
2023
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28. Numerical Voltammetry of Phase Separating Materials Using Phase Field Modeling.

Author

Hussain, Umair, Swaminathan, Narasimhan, and Phanikumar, Gandham

Subjects
VOLTAMMETRY, PHASE separation, LITHIATION
Abstract

Higher capacity materials, such as Si and Sn are known to have phase separating behavior during the (de)lithiation. While initial models for lithiation in graphite electrode were based on single phase diffusion, with the introduction of Si and Sn, disposition of the models has shifted to the two-phase diffusion. It is important to understand the interaction of various phenomenon in materials which show phase change during (dis)charging cycles. In this work, we present a phase field model to simulate two-phase lithiation. This model is used to study the electrochemical response of the system by conducting numerical voltammetry. The main goal of this effort is to highlight the difference in electrochemical response occurring during single-phase diffusion and two-phase diffusion and explain the ensuing physics. Furthermore, effect of elasticity which governs the phase-change process and also alters corresponding voltammograms is also studied in detail. The voltammograms show clear shift in current peaks' size and position for the changing diffusion behavior. Also as elasticity affects the two-phase diffusion, change in nucleation timing and diffusion rate are visible in voltammograms. Additionally, it is also observed how elasticity can cease the phase separation behavior and voltammogram for two-phase diffusion can become identical to single-phase diffusion. [ABSTRACT FROM AUTHOR]

Published
2024
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46. Constitutive Behavior With Microstructure and Texture Evolution During the High-Temperature Deformation of Fe11.5Co20.6Ni40.7Cr12.2Al7.8Ti7.2 High-Entropy Alloy.

Author

Kumar, Piyush, Rahul, M. R., Samal, Sumanta, Ghosh, Abhijit, and Phanikumar, Gandham

Subjects
STRAINS & stresses (Mechanics), NICKEL-chromium alloys, MICROSTRUCTURE, DEFORMATIONS (Mechanics), STRAIN rate, STRESS-strain curves, ALLOYS
Abstract

Microstructure and texture evolution of the Fe11.5Co20.6Ni40.7Cr12.2Al7.8Ti7.2 (at. pct) high-entropy alloy during the high-temperature deformation has been investigated in the temperature range of 1173 K to 1373 K and strain rate of 0.1 to 0.001 s−1. The stress–strain curve obtained from the deformation indicates significant flow softening at low temperatures. The softening at 1173 K is due to cracking, whereas high-temperature softening is attributed to dynamic recrystallization (DRX). Arrhenius-type sine hyperbolic relationship is used to carry out the flow stress analysis, and the predicted flow stress shows good agreement with the experimental results with an accuracy of (R2 = 0.955), especially when the deformation takes place at a low strain rate. The estimated strain hardening exponent, n (> 3), and activation energy, Q (> 400 kJ/mol), indicated that the deformation mechanism is dislocation controlled. Detailed microstructural and textural characterization of the hot deformed sample has been carried out using EBSD analysis. Microstructural investigation confirms that dynamic recrystallization is the primary reason behind the flow softening for the samples deformed at 1273 K and above. Strain-free recrystallized grains are found to nucleate near the grain boundary region. Furthermore, the size of the recrystallized grains increases with an increase in temperature and a decrease in strain rate. The volume fraction of the recrystallized grains is found to decrease with an increase in the Zener Holloman parameter. DRX grain was found to possess a weak texture with a low texture index. [ABSTRACT FROM AUTHOR]

Published
2023
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