Full Revision

Question 1

Hall Petch Equation?

Answer 1

deltayield= deltao + ky*d^-1/2

Question 2

%CW

Answer 2

(Ao-Ad/Ao)x100

Question 3

What is a Phase Diagram?

Answer 3

Is a representation of the relationships between temperature and the compositions and the quantities of phases in equilibrium.

Question 4

Between the liquidus line & solidus line?

Answer 4

Island of solid material in liquid material

Question 5

Lever Rule

Answer 5

S/S+R= (Calpha-Co/Calpha-Cl)

Question 6

Effecting of Heating after Cold work: Recovery Stage

Answer 6

Allows dislocations to “move” and increases the possibility of annihilation => lowering dislocation density

Question 7

Effect of Heating after cold work: Recrystallization Stage

Answer 7

New grains are formed that:

• have a small dislocation density
• are small
• consume cold-worked grains

Question 8

Rolling metal is a forming technique:

Answer 8

that involves decreasing the thickness of the material.

Question 9

Extruding metal is a forming technique:

Answer 9

that involves pushing a material through a small orifice.

Question 10

Forging metal is a forming technique:

Answer 10

that involves hammering the material in shape.

Question 11

Diffusion of atoms from one metal into another metal is known as:

Answer 11

interdiffusion, or impurity diffusion.

Question 12

An isotropic material property is a material property that is

Answer 12

the same in all directions.

Question 13

Which bond is directional?

Answer 13

Covalent bonds.

Question 14

Coordination number, unit number of atoms and atomic packing factor of BCC

Answer 14

Coordination number: 8
Unit number:

N = Ni + Nf/2 + Nc/8 = 2

Question 15

A crystalline defect refers to:

Answer 15

A lattice irregularity having one or more of its dimensions on the order of an atomic diameter.

Question 16

Necessity of Vacancies in metals:

Answer 16

The presence of vacancies increases the entropy of the crystal.

Question 17

What is a self-interstitial?

Answer 17

An atom from the crystal that is crowded into an insterstitial site, a small void space that under ordinary circumstances is not occupied.

Question 18

What does a interstitial introduce in a metal?

Answer 18

interstitual introduces relatively large distortions in the surrounding lattice because the atom is substantially larger than the interstitial position in which it is situated. Consequently, the formation of this defect is not highly probable, and it exists in very small concentrations that are significantly lower than for vacancies.

Question 19

Two types of impurities in solid solutions?

Answer 19

substitutional and interstitial

Question 20

Substitutional impurity(metals):

Answer 20

Solute or impurity atoms replace or substitute for the host atoms.

Question 21

The 4 factors that determine how successful an impurity dissolves in a metal host. (Hume-Rothery Rules).

Answer 21

1. Atomic size factor
2. Crystal Structure
3. Electronegativity factor
4. Valences

Question 22

FCC:

Answer 22

Face-centered cubic crystal structure

Atoms located at each of the corners and the centers of all the cube faces.

Question 23

Single Crystal:

Answer 23

When the periodic and repeated arrangement of atoms is perfect or extends throughout the entirety of the specimen without interruption.

Question 24

Grain Boundary:

Answer 24

some atomic mismatch within the region where two grains meet.

Question 25

Texture:

Answer 25

When the grains in a polycrystalline have a preferential crystallographic orientation.

Question 26

Amorphous solid:

Answer 26

When a solid has a noncrystalline structure. | Their structure resembles that of a liquid.

Question 27

Three main metal crystal structures:

Answer 27

FFC: Face-centered cubic BCC: Body-centered cubic HCP: Hexagonal close-packed

Question 28

FCC cube edge length a:

Answer 28

a= 2R* Sqrt[2]

Question 29

Coordination number,number of atoms and atomic packing factor in FCC?

Answer 29

Coordination number = 12 N = Ni + Nf/2 + Nc/8 = 4 APF = 0.74

Question 30

Coordination number:

Answer 30

number of nearest-neighbour or touching atoms of each atom.

Question 31

Atomic Packing Factor(APF):

Answer 31

The APF is the sum of the sphere volumes of all atoms within a unit cell divided by the unite cell volume. APF= Volume of atoms in a unit cell/ total unit cell volume

Question 32

BCC:

Answer 32

Body-centered structure Atoms located at all eight corners and a single atom at the cube center.

Question 33

BCC unit cell length a:

Answer 33

a= 4R/sqrt[3]

Question 34

Rule of Mixtures?

Answer 34

Sum of Modulus * percentage composition