Chapter 5

1. What does the 'b' in the lattice type bcc stand for?

• Base

• Body

• Bohr

• Basal

2. Arrange the three lattice types bcc, fcc, and hcp by increasing number of slip systems.

• bcc < fcc < hcp

• hcp < bcc < fcc

• fcc < bcc < hcp

• hcp < fcc < bcc

3. Which stresses are responsible for the gliding of dislocations?

• Tensile stresses

• Compression stresses

• Shear stresses

• Torsion stresses

4. Which of these obstacles in a typical polycrystalline microstructure is 2-dimensional?

• Grain boundary

• Impurity atom

• Precipitate

• Dislocation

5. Which of the following assignments between the type of obstacle and the effect is incorrect?

• Impurity atom – single crystal hardening

• Precipitates – particle hardening

• Dislocation – strain hardening

• Grain boundary – grain refinement

6. Which of these hardening mechanisms is positively affected by increased temperatures (T > 0.4 Ts)?

• Strain hardening

• Grain refinement

• Particle hardening

• Cyclic hardening

7. What is the mechanism involved in particle hardening for incoherent and big coherent particles?

• Basquin

• Kelly and Fine

• Orowan

• Woehler

8. Edge and screw dislocations with opposite orientation on the same lattice plane…

• Enhance each other

• Do not influence each other

• Are balanced, and annihilate each other

• Will lead to abrupt failure