Imperfections in Solids - Chapter 6

Question 1

Crystalline Defect

Answer 1

A crystallline defect refers to a lattice irregularity having one or more of its dimensions on the order of an atomic diameter.

Question 2

Vacancy?

Answer 2

When one normally occupied but from which an atom is missing.

Question 3

Self-interstitual

Answer 3

A self interstitial is an atom from the crystal that is crowded into an interstitial site - a small void space that under ordinary circumstances is not occupied.

Question 4

How does a self-interstitual effect a crystal?

Answer 4

In metals, a self interstitual introduces relatively large distortions in the surrounding lattice because the atom is substantially larger than the interstitual position in which it is situated.

Question 5

Solvent and Solute?

Answer 5

Solvent: the element or compound that is present in the greatest amount, also known as host atoms.

Solute: the element or compound present in minor concentration.

Question 6

Two types of impurity point defects found in solid solutions?

Answer 6

Substitutional and interstitial

Question 7

Substitutional?

Answer 7

impurity/solute atoms replace or substitute the host atoms..

Question 8

The four Hume-Rothery rules that determine degree of of solvent.

Answer 8

1. Atomic Size Factor
2. Crystal structure
3. Electronegativity factor
4. Valences

Question 9

Properties of grain boundaries

Answer 9

1. Atoms are bonded less regularly along a grain boundary.
2. Grain boundary energy is similar to the surface energy.
3. Impurity atoms often preferentially segregate along these boundaries because of their higher energy state.