Experimental and Molecular Dynamic Study of Grain Refinement and Dislocation Substructure Evolution in HSLA and IF Steels after Severe Plastic Deformation

Krzysztof Muszka,Dawid Zych,Lukasz Madej,Paulina Lisiecka-Graca,Janusz Majta

doi:10.3390/met10091122

Krzysztof Muszka, Dawid Zych + Show 3 more

Open Access

https://doi.org/10.3390/met10091122

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Journal: Metals	Publication Date: Aug 21, 2020
Citations: 8	License type: CC BY 4.0

Affiliation: AGH University of Krakow

Abstract

In this study, large-scale molecular dynamic simulations were performed to analyze the dislocation substructure interaction with various types of obstacles present in microalloyed steels during severe plastic deformation. Specifically, fully functional numerical models of the atomic upsetting test were developed, with particular emphasis on the presence of precipitates inside the microstructure grains. The obtained results compared with the microstructural tests, performed using Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscope (TEM) techniques, allowed for a more accurate assessment of the microstructure refinement mechanisms by means of the in-situ recrystallization effect in the deformed samples subjected to the multi-axis compression using the MaxStrain system (Dynamic Systems Inc., New York, NY, USA).

Highlights

The fundamental challenge of pursuing computer simulation accuracy and efficiency is the same in both manufacturing and materials sciences, computer modelling of physical phenomena in materials has special concerns because of significant diversity in the chemical and structural compositions
Investigated in the present study, high strength low alloy (HSLA), as a common structural material, gives many new application possibilities, which result from ultrafine-grained microstructures produced with the use of severe plastic deformation (SPD) techniques
Scanning Electron Microscopy (SEM)/Electron Backscatter Diffraction (EBSD), grainof accumulative equivalent bothofby means of strain, Transmission Electron Microscope (TEM) and that strong refinement is visible after thestrain

Summary

Introduction

The fundamental challenge of pursuing computer simulation accuracy and efficiency is the same in both manufacturing and materials sciences, computer modelling of physical phenomena in materials has special concerns because of significant diversity in the chemical and structural compositions. The microstructure, thermodynamic, rheological and mechanical properties of materials are strongly dependent on conditions such as chemical composition, lattice structure, stacking fault energy, temperature, and strain rate Due to these special concerns, the underlying interaction models are diverse, and new simulation methods are often required to obtain statistically meaningful results. Investigated in the present study, high strength low alloy (HSLA), as a common structural material, gives many new application possibilities, which result from ultrafine-grained microstructures produced with the use of severe plastic deformation (SPD) techniques. The obtained results compared with the microstructural tests, performed using EBSD and TEM techniques, allowed for a more accurate assessment of the microstructure refinement mechanisms by means of the in-situ recrystallization effect in the deformed samples subjected to the SPD at the MaxStrain system [12].

Materials and Methods

Results and Discussion

Geometrically necessary dislocations’

Modeling

Evolution of defects during compression of grains with with