Precipitation of carbides

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Table of contents

Chapter I: Backround for the iron aluminides based intermetallics analysis
I. Intermetallic compounds
II. Iron aluminides
III. Bulk strengthening
III.1 Strengthening by solid-solution hardening
III.2. Strengthening by incoherent precipitates
III.2.1. Precipitation of intermetallic phases
III.2.2. Precipitation of carbides
III.3. Strengthening by coherent precipitates
III.4. Strengthening by order
III.4.1. Site preference
III.4.2. Solute effects on D03 ordering
III. 5 Objective of our work for bulk analysis
IV. Effect of alloying elements on ductility
IV. 1 Boron addition and grain boundary strength
IV. 2. Transition metal additions
IV. 3 Modelling approach and objectives of our G.B. simulations
References
Chapter II: Theoretical tools
Part A: Ab Initio Molecular Dynamics
I.1. Introduction
I.2. Quantum Molecular Dynamic
I.2.1. Deriving Classical Molecular Dynamics
I.2.2. « Ehrenfest » Molecular Dynamics
I.2.3. « Born-Oppenheimer » Molecular Dynamics
I.2.4. « Car-Parrinello » Molecular Dynamics
I.3. Integration of the equations of motion
I.3.1. Hamiltion’s point of view and statistical mechanics
I.3.2. Microcanonical Ensemble
I.3.3. The molecular dynamics propagators
I.3.4. Extended System Approach
I.3.4.1. Barostats
I.3.4.2. Thermostats
References:
Part B: The Electronic Structure Methods
II. 1. Introduction
II. 2. Density Functional Theory
II. 3. Energy functionals
II. 4. The plane wave pseudopotential method
II.4.1. Plane waves
II.4.1.1. Supercell
II.4.1.2. Fourier representations
II.4.1.3. Bloch’s Theorem
II.4.1.4. k–Point Sampling
II.4.1.5. Fourier representation of the Kohn-Sham equations
II.4.1.6. Fast Fourier Transformation (FFT)
II.4.2. Pseudopotentials
II.4.2.1. Norm conserving Pseudopotentials
II.4.2.1.1. Hamann–Schluter–Chiang conditions
II.4.2.1.2 Bachelet-Hamann-Schluter (BHS) form
II.4.2.1.3. Kerker Pseudopotetials
II.4.2.1.4. Trouiller–Martins Pseudopotentials
II.4.2.1.5. Kinetic Energy Optimized Pseudopotentials
II.4.2.2. Pseudopotentials in the Plane Wave Basis
II.4.2.2.1. Gauss–Hermit Integration
II.4.2.2.2. Kleinman–Bylander Scheme
II.4.2.3. Non-linear Core Correction
II.4.2.4. Ultrasoft Pseudopotentials Method
References
Chapter III: Static ab initio calculations (0K)
I. Computational details
I.1. Computational method
I.2. Structural properties
I.3. Energetics
II. Point defects in bulk Fe3Al
II.1. Importance of relaxation
II.2. The site preference of point defects in the bulk D03-Fe3Al
III. Impurity segregation at grain boundaries
III.1. Crystal structures and location of structural defects
III.2. Site preference and effect of Ti and Zr on the grain boundary cohesion
III.3. Charge density distribution
III.4. Impurities induced bonding charge density
III. 5. The relaxation of the clean grain boundary
III.5. The relaxation of the doped grain boundary
IV. Summary and Conclusion
References
Chapter IV: Ab initio molecular dynamics calculations
I. Calculation details
I. 1. Computational methods
I. 2. Preliminary calculations
I.3. Energetic
II. Transition metal impurities in the bulk D03-Fe3Al
II.1. Site preference of the Ti and Zr substitutions
II.2. Structural and stability results
II.2.1. Equilibrium lattice parameters
II.2.2. Pair distribution function
II.2.2.1. Pair distribution functions for D03-Fe3Al
II.2.2.2. Pair distribution functions for doped Ti and Zr-Fe3Al
III. Transition metals segregation in 5 (310) [001] grain boundary
III.1. Site preference of Ti and Zr in the 5(310)[001]
III.2. The effect of temperature on the structural relaxation of 5 grain boundary
III.2.1. Relaxation of the clean grain boundary
III.2.2. Relaxation of the doped grain boundary at 300K
IV. Summary and conclusion
Reference