Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Teaching & Learning Packages Dislocation Energetics Join the crystals to form the dislocation
Dislocation Energetics AimsBefore you startIntroductionMaking a dislocationJoin the crystals to form the dislocationDislocation widthForm of the displacementChange in the misfit energy of a dislocation as it movesPeierls energyWhat is the Peierls stress? Determining the Peierls stressLattice resistanceUses and limitations of the atomistic modelSummaryQuestionsGoing further
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Join the crystals to form the dislocation

We have determined that the displacements of the atoms are:

\[{u_A}\left( x \right) = - \frac{b}{{2\pi }}ta{n^{ - 1}}\left( {\frac{{{x_A}}}{w}} \right)\]

\[{u_B}\left( x \right) = - \frac{b}{{2\pi }}ta{n^{ - 1}}\left( {\frac{{{x_B}}}{w}} \right)\]

From below, the displacements of the atoms on the A-plane are symmetrical on either side of the dislocation line, and are zero at the centre. It is clear that the misfit around the dislocation is of two types: a strain in the planes above and below the dislocation and a misalignment of the atoms across the slip plane.

The process of determining the energies is shown in the following animation:

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