Crystal Plasticity Simulation of in-grain Microstructural Evolution during Large Plastic Deformation

The capability of high-resolution modeling of crystals subjected to large plastic strain is essential in predicting many important phenomena occurring in polycrystalline materials, such as microstructure, deformation localization, and in-grain texture evolution. However, due to the heterogeneity of the plastic deformation in polycrystals, the...

Determination and analysis of the constitutive parameters of temperature-dependent dislocation-density-based crystal plasticity models

Physics-based crystal plasticity models rely on certain statistical assumptions about the collective behavior of dislocation populations on one slip system and their interactions with the dislocations on the other slip systems. One main advantage of using such physics-based constitutive dislocation models in crystal plasticity kinematic...

Strain partitioning and damage initiation in a continuously cooled carbide free bainitic steel

Microscopic stress and strain partitioning control the mechanical and damage behavior of multiphase steels. Using a combined numerical and experimental approach, local strain distributions and deformation localization are characterized in a carbide free bainitic steel produced by continuous cooling. The microstructure of the steel consists of...

Analysis of work hardening mechanisms in Quenching and Partitioning steels combining experiments with a 3D micro-mechanical model

Quenching & Partitioning (Q&P) steels owe their good strength-ductility combinations to the martensite/austenite (α’/γ) mechanical interactions and to the formation of mechanically-induced martensite (α′_mech) through the transformation-induced plasticity (TRIP) effect. An essential role is played by carbon, whose...

Crystal plasticity simulation of in-grain microstructural evolution during large deformation of IF-steel

High-resolution three-dimensional crystal plasticity simulations are used to investigate deformation heterogeneity and microstructure evolution during cold rolling of interstitial free (IF-) steel. A Fast Fourier Transform (FFT)-based spectral solver is used to conduct crystal plasticity simulations using a dislocation-density-based crystal...

Influence of Microstructure on Mechanical Properties and Damage Initiation of Bainitic Steels in Railway Applications

In this PhD thesis, we investigated possible steel candidates for use in railway crossings in order to reduce the damage in them. Pearlitic R350HT together with Bainitic grades including CrB, B1400 and carbide free B360 were investigated for their mechanical properties such as ultimate strength, yield strength, ductility and hardness. The...

Investigation of crystallographic disorientation topology in simulation of rolling textures with the ALAMEL model

The crystallographic texture of a material has a direct impact on its mechanical and functional properties. As a result, texture control is an imperative part of manufacturing processes, especially those involving plastic deformation, such as rolling, which significantly impact crystallographic texture. The exact mechanisms and underlying causes...

Crystallographic texture control in a non-oriented electrical steel by plastic deformation and recrystallization

Texture and anisotropy are persistent characteristics of polycrystal. Because of the ordered and periodic arrangement of atoms in crystal lattices, responses of each oriented crystals in a polycrystal to the same external forces are not similar. Crystal grains which are better accommodated to boundary conditions because of their energetically...

Large-deformation crystal plasticity simulation of microstructure and microtexture evolution through adaptive remeshing

The capability of high-resolution modeling of crystals subjected to large plastic strain is essential in predicting many important phenomena occurring in polycrystalline materials, such as microstructure, deformation localization and in-grain texture evolution. However, due to the heterogeneity of the plastic deformation in polycrystals, the...

Advanced Crystal Plasticity Modeling of Multi-Phase Steels: Work-Hardening, Strain Rate Sensitivity and Formability

This work presents an advanced crystal plasticity model for the simulation of the mechanical behavior of multiphase advanced high-strength steels. The model is based on the Visco-Plastic Self-Consistent (VPSC) model and uses information about the material’s crystallographic texture and grain morphology together with a grain constitutive law. The...

The effect of hydrogen content and yield strength on the distribution of hydrogen in steel: a diffusion coupled micromechanical FEM study

In this study, we investigate the effect of the heterogeneous micromechanical stress fields resulting from the grain-scale anisotropy on the redistribution of hydrogen using a diffusion coupled crystal plasticity model. A representative volume element with periodic boundary conditions was used to model a synthetic microstructure. The effect...

Influence of M₂₃C₆ carbides on the heterogeneous strain development in annealed 420 stainless steel

Understanding the local strain enhancement and lattice distortion resulting from different microstructure features in metal alloys is crucial in many engineering processes. The development of heterogeneous strain not only plays an important role in the work hardening of the material but also in other processes such as recrystallization and...

Use of the Correlation between Grain Size and Crystallographic Orientation in Crystal Plasticity Simulations: Application to AISI 420 Stainless Steel

Crystal plasticity models attempt to reproduce the complex deformation processes of polycrystalline metals based on a virtual representation of the real microstructure. When choosing this representation, a compromise must be made between level of detail at the local level and statistical significance of the aggregate properties, also taking into...

An efficient and robust approach to determine material parameters of crystal plasticity constitutive laws from macro-scale stress-strain curves

A severe obstacle for the routine use of crystal plasticity models is the effort associated with determining their constitutive parameters. Obtaining these parameters usually requires time-consuming micromechanical tests that allow probing of individual grains. In this study, a novel, computationally efficient, and fully automated approach is...

From micro-mechanisms of damage initiation to constitutive mechanical behavior of bainitic multiphase steels

Global warming, continuous demand on energy from fossil fuels as a limited natural resource, and costumers’ high expectations regarding product quality are three global challenges that the automotive industry is facing. Fuel consumption reduction has a significant impact on preserving fossil fuels, lowering fossil fuel dependency and the CO2...

Micromechanical modeling and simulations of transformation-induced plasticity in multiphase carbon steels

Crystallographically based model for transformation-induced plasticity in multiphase carbon steels

The microstructure of multiphase steels assisted by transformation-induced plasticity consists of grains of retained austenite embedded in a ferrite-based matrix. Upon mechanical loading, retained austenite may transform into martensite, as a result of which plastic deformations are induced in the surrounding phases, i.e., the ferrite-based...