Exercise 5.1-1

Sign of Burgers and Line Vectors

Lets look at a dislocation loop in cross-section. After the "cut" along the red line, the lower half was moved to the right by b. Two edge dislocation are visible if we look at a cross-section taken through the middle of the loop. A Burgers circuit now would give Burgers vectors of different signs - or does it?

We can ask the same question in a different way: From the Volterra construction we know that the Burgers vector - including the sign - must be the same everywhere. But the dislocations shown in the cross section look "reversed" - we would certainly assign different signs just looking at the picture. How is this contradiction to be solved?

Link to the solution

With frame

5.1.2 Volterra Construction and Consequences

Solution to Exercise 5.1-1