Chapter 7 (Dislocations & Strengthening)

Question 1

in what type of material are dislocations most commonly found?

Answer 1

Metals

Question 2

why are metals more prone to dislocations?

Answer 2

1. because of non-directional bonding

2. because they are closed packed

Question 3

why are covalent materials less prone to dislocations

Answer 3

because of their angular bonding

Question 4

what type of deformations are caused by plastic deformation?

Answer 4

Plastic deformations

Question 5

what requires LESS STRESS breaking a material or deforming it.

Answer 5

Deforming it

Question 6

what is a slip system comprised of

Answer 6

a slip direction and a slip plane

Question 7

which planes are typically favored by slip systems

Answer 7

the more closely packed ones; eg FCC

Question 8

what can be said about same sign dislocations versus opposite sign dislocations

Answer 8

same signs repel, opposite signs attract and annihilate upon joining (no more dislocation)

Question 9

give an example of a slip system for FCC

Answer 9

{111},

Question 10

why are HCP metals brittle

Answer 10

because they have FEW slip systems

Question 11

what can be said about ionically bonded materials regarding slip

Answer 11

they are able to resist slip due to disruptions in charge balance