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Main Authors: Pai, Namit, Samajdar, Indradev, Patra, Anirban
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2403.11080
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author Pai, Namit
Samajdar, Indradev
Patra, Anirban
author_facet Pai, Namit
Samajdar, Indradev
Patra, Anirban
contents Rapid solidification in Additively Manufactured (AM) metallic materials results in the development of significant microscale internal stresses, which are attributed to the printing induced dislocation substructures. The resulting backstress due to the Geometrically Necessary Dislocations (GNDs) is responsible for the observed Tension-Compression (TC) asymmetry. We propose a combined Phase Field (PF)-Strain Gradient $J_2$ Plasticity (SGP) framework to investigate the TC asymmetry in such microstructures. The proposed PF model is an extension of Kobayashi's dendritic growth framework, modified to account for the orientation-based anisotropy and multi-grain interaction effects. The SGP model has consideration for anisotropic temperature-dependent elasticity, dislocation strengthening, solid solution strengthening, along with GND-induced directional backstress. This model is employed to predict the solute segregation, dislocation substructure and backstress development during solidification and the post-solidification anisotropic mechanical properties in terms of the TC asymmetry of rapidly solidified Fe-Cr alloys. It is observed that higher thermal gradients (and hence, cooling rates) lead to higher magnitudes of solute segregation, GND density, and backstress. This also correlates with a corresponding increase in the predicted TC asymmetry. The results presented in this study point to the microstructural factors, such as dislocation substructure and solute segregation, and mechanistic factors, such as backstress, which may contribute to the development of TC asymmetry in rapidly solidified microstructures.
format Preprint
id arxiv_https___arxiv_org_abs_2403_11080
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Microstructural and Mechanistic Insights into the Tension-Compression Asymmetry of Rapidly Solidified Fe-Cr Alloys: A Phase Field and Strain Gradient Plasticity Study
Pai, Namit
Samajdar, Indradev
Patra, Anirban
Materials Science
Rapid solidification in Additively Manufactured (AM) metallic materials results in the development of significant microscale internal stresses, which are attributed to the printing induced dislocation substructures. The resulting backstress due to the Geometrically Necessary Dislocations (GNDs) is responsible for the observed Tension-Compression (TC) asymmetry. We propose a combined Phase Field (PF)-Strain Gradient $J_2$ Plasticity (SGP) framework to investigate the TC asymmetry in such microstructures. The proposed PF model is an extension of Kobayashi's dendritic growth framework, modified to account for the orientation-based anisotropy and multi-grain interaction effects. The SGP model has consideration for anisotropic temperature-dependent elasticity, dislocation strengthening, solid solution strengthening, along with GND-induced directional backstress. This model is employed to predict the solute segregation, dislocation substructure and backstress development during solidification and the post-solidification anisotropic mechanical properties in terms of the TC asymmetry of rapidly solidified Fe-Cr alloys. It is observed that higher thermal gradients (and hence, cooling rates) lead to higher magnitudes of solute segregation, GND density, and backstress. This also correlates with a corresponding increase in the predicted TC asymmetry. The results presented in this study point to the microstructural factors, such as dislocation substructure and solute segregation, and mechanistic factors, such as backstress, which may contribute to the development of TC asymmetry in rapidly solidified microstructures.
title Microstructural and Mechanistic Insights into the Tension-Compression Asymmetry of Rapidly Solidified Fe-Cr Alloys: A Phase Field and Strain Gradient Plasticity Study
topic Materials Science
url https://arxiv.org/abs/2403.11080