
Draw a schematic lattice fringe picture of a screw
dislocations by sketching the planes above and below the dislocation line 


Produce the dislocation arrangement shown in the
picture by Volterra cuts and determine the Burgers vector of the third
dislocation. 

Enumerate at least 5 basic properties of
dislocations. 

What do you know about the free enthalpy and so on
of a dislocation? What is the source of the enthalpy (or energy) of a
dislocation? Give a number and discuss consequences for (global and local)
equilibrium. 

What is the difference between an edge and a screw
dislocation? 




Determine the Burgers vector of the dislocation
shown. Here are some hints. 



Try to identify the unit cell first. 


The picture shows a projection of a fcc
lattice along a <110> direction 


The crystal is of the diamond type 


If all else fails  use
this link 




The thee dislocations shown (in black, red and
blue) were made by two successive Volterra cuts. 



Three dislocations = three Burges vectors. How can you
determine the three Burgers vectors by the properties of the two cuts? 


Can you obtain this basic geometry by just one cut? 


If yes, what would kind of Burgers vector would you find in
this case for the red line? 


