3. Crystal Structure and Defects

Line Defects — Quiz

Test your understanding of line defects with 5 practice questions.

Practice Questions

Question 1

What force per unit length does a dislocation experience under an applied shear stress, given a screw dislocation with Burgers vector magnitude $b=0.25\times10^{-9}\,$m, an applied shear stress $\tau=100\,$MPa, and segment length $L=1\,\mu$m?

Question 2

What is the magnitude of the Burgers vector for a Shockley partial dislocation in an FCC crystal with lattice parameter $a=0.361\,$nm?

Question 3

In an FCC crystal, compare the line energy of a Shockley partial to that of a perfect dislocation given $E\propto b^2$. What is the ratio $E_{partial}/E_{perfect}$?

Question 4

According to the von Mises criterion for arbitrary homogeneous plastic deformation, what is the minimum number of independent slip systems required in a crystal?

Question 5

Which dislocation motion mechanism is most severely limited at low homologous temperatures due to its reliance on vacancy diffusion?