Plastic Deformation of Nanostructured Materials

A.M. Glezer, E.V. Kozlov, N.A. Koneva, N. A. Popova, I. A. Kurzina

• Publisher: CRC Press
• Year: 2017
• Print ISBN: 9781138077898
• eBook ISBN: 9781351620598
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Chemistry
• Index: Chemistry

Plastic Deformation of Nanostructured Materials offers comprehensive analysis on the most important data and results in the field of materials strength and mechanics. This reference systematically examines the special features of the mechanical behavior and corresponding structural mechanisms of crystal structure defects with grain sizes that range from meso- to micro- levels.

Contents

Introduction

1. Stages of plastic deformation of polycrystalline materials

1.1. Introduction. Description of the problem

1.2. Main stages of plastic deformation of polycrystals at themesolevel

1.3. Determination of the plastic deformation stages in FCCmetals and solid solutions

1.4. Some historical data for the determination of the stagesII-IV of plastic deformation in polycrystalline materials

1.5. Individual stages of plastic deformation in the BCC metals and alloys

1.6. Storage of dislocations, internal stress fields andevolution of the dislocation structure

1.7. Evolution of the substructure - the basics of the physicsof stages in gliding of total dislocations

1.8. Transition to twinning and deformation martensitictransformation as an important factor of formation ofstages of work hardening

1.9. Localisation of deformation - another reason for theformation of new stages

1.10. Factors complicating the characteristics of thedeformation stages in meso-polycrystals

1.11. Effect of the mesograin size on the individual stages ofplastic deformation

1.12. Changes of the structure of the polycrystallineaggregate and the pattern of the deformation stages with adecrease of the average grain size

1.13. The main factors determining the stages of deformation and the value of the work hardening coefficient in the microrange

1.14. Problem of determination of the grain size at themicrolevel

1.16. The stress σ-strain ε dependence for copper polycrystals with different nanograin sizes

1.17. Relationships of work hardening of copper micropolycrystals with different grain sizes

1.18. Hardening mechanisms and special features of theindividual stages of deformation of polycrystals withnanograins

1.19. Effect of different hardening mechanisms on the flowstress and the form of the σ = f (ε) dependence

1.20. Basic pattern of work hardening of nanocrystals

1.21. Effect of the grain size on the parameters of plasticdeformation stages

2. The structure and mechanical properties of nanocrystals

2.1. Introduction

2.2. Classification of polycrystals on the basis of the grain size

2.3. Methods for producing ultrafine-grained and nanograin polycrystalline materials

2.4. The structure of polycrystalline materials

2.5. Triple junctions in grains

2.6. Models of polycrystalline grains at the meso-and microlevel

2.7. The structure of individual nanograins

2.8. Special features of the structure of the nanopolycrystal- line aggregate as a consequence of high plastic strains

2.9. Dependence of the dislocation density on the grain size and the problem of fine grains without dislocations

2.10. Critical size ranges of the grains and areas with grains

2.11. The Hall-Petch relation and its parameter σ₀ in a wide grain size range

2.12. The mechanisms of implementation of the Hall-Petch relation at the mesolevel

2.13. Dependence of coefficient k on the grain size in the Hall-Petch relation

2.14. Problem of the transition of coefficient k to negative value. The first critical grain size

2.15. Mechanisms of realisation of the Hall-Petch relation at the microlevel

2.16. Mechanisms providing contribution to the grain boundary sliding process

2.17. The number of dislocations in the shear zone and the stress, required for the formation of this zone

2.18. Contact stresses. Conventional and accommodation sliding

2.19. Conclusion

3. Main components of the dislocation structure and the role of the dimensional factor

3.1. Problem of classification of dislocation structure components

3.1.1. Components of the dislocation structure

3.1.2. Strain gradient, the density of geometrically necessary and excess dislocations

3.1.3. Grain size and the density of geometrically necessary dislocations

3.1.4. Methods of measuring the density of geometrically necessary dislocations

3.2. The scalar density of dislocations in dislocation fragments with different types of substructure

3.2.1. Dependence of the dislocation density on the grain size in ultrafine-grainedpolycrystals

3.2.2. Critical grain sizes

3.2.3. Geometrically necessary and statistically stored dislocations, the second and third critical grain sizes. Comparison of the parameters of the micro- and mesolevel

3.3. Dependence of the scalar density of the dislocations on the size of the fragments with the network dislocation substructure in a martensitic steel

3.4. Dependence of dislocation density on the size of fragments with the cellular dislocation substructure in the martensitic steel

3.5. Effect of the size of the fragments of grains and on the density of defects in metallic materials

3.5.1. Similarity of the dimensional relationships in ultrafine‐ grained polycrystals of metals and steels with a fragmented structure

3.5.2. Dependence of the density of partial disclinations on the grain size

3.5.3. Particles of second phases, dislocations and boundaries of grains and fragments

3.5.4. Plastic deformation and nanoparticles of second phases in microcrystalline metals

3.5.5. Fragmented dislocation substructure in martensitic steels and second phase microparticles

3.5.6. Mechanisms of formation of second phase particles at the boundaries of elements of the microstructure

3.5.7. Stabilisation of the structure of microcrystals by second phase particles

3.6. The role of geometrically necessary dislocations in the formation of deformation substructures

3.7. Storage of geometrically necessary dislocations and scalar dislocation density. The role of boundaries of different type

3.8. Concentration dependence of the main parameters of the dislocation structure in the FCC solid solutions

3.9. Cellular substructure: dislocation density ρ_S and ρ_G and the cell size

4. Dislocation structure and internal stress fields

4.1. Introduction

4.2. Methods for measuring internal stresses

4.3. Structure of ultrafine-grained metals and alloys

4.4. Sources of internal stress fields in ultrafine-grained materials

4.5. Distribution of internal stresses in grains. The scheme of the grains of ...

Table of contents

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• Halftitle
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• Table of Contents