21: Dislocation Energetics and Mobility — Read

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www.doitpoms.ac.uk/tlplib/me...ng-2/index.php

Learning Objectives

On completion of this TLP you should:

Understand why a dislocation forms and how the dislocation width can be determined using an atomistic model, by minimisation of misfit energy due to in-plane stress and misalignment.
Appreciate how the energy changes as a dislocation moves and how the parameters of atomic spacing, Shear modulus and Poisson ratio affect the total misfit energy.
Be familiar with the concepts of Peierls stress and lattice resistance and compare theoretical and experimental values. Also understand the difference between the linear elastic analytic solution used by Peierls and the atomistic model.

Before you start

Look through the TLP on Introduction to Dislocations
- https://www.doitpoms.ac.uk/tlplib/dislocations/index.php
These pages on dislocation width and Peierls Nabarro stress will be particularly useful.
- https://www.doitpoms.ac.uk/tlplib/dislocations/dislocationwidth.php
- https://www.doitpoms.ac.uk/tlplib/dislocations/slip_via_dislocation.php
This LD shows what happens when dislocations interact to cause work hardening. It also covers the formation of dislocations (Frank Read sources).
- https://www.doitpoms.ac.uk/ldplib/work-hardening-polycrystals/index.php

This page titled 21: Dislocation Energetics and Mobility was last modified on Thu, 26 Nov 2020 20:30:58 GMT and is shared under a CC BY-NC-SA 2.0 license and was authored, remixed, and/or curated by Dissemination of IT for the Promotion of Materials Science (DoITPoMS) via source content that was edited to the style and standards of the LibreTexts platform.

Contents

Text

Before you start