Fundamentals Of Metals (basic Metallurgy)

Question 1

Define a substitution alloy

Answer 1

Mixture of different type of atoms

Question 2

Define an interstitial alloy

Answer 2

The atoms slip between each other

Question 3

Define phase of a solid solution alloy

Answer 3

A homogenous portion of a system that has the same physical and chemical characteristics

Question 4

Define solid solution

Answer 4

A homogenous crystalline phase that contains two or more chemical species

Question 5

Define solubility limit

Answer 5

A specific temperature where there is a maximum concentration of solute atoms that may dissolve to form a solid solution.

Question 6

Define equilibrium

Answer 6

When a systems free energy is at a minimum under some specified combination of temperature, pressure and composition

Question 7

Give an example of a substitutional alloy

Answer 7

Brass

Question 8

Name the stages of the solidification of materials

Answer 8

Liquid metal/ solid solution 
Embryo
Nucleus 
(Dendrites)
Grains

Question 9

Define a grain

Answer 9

An individual crystal in a polycrystalline metal or ceramic

Question 10

Define grain boundary

Answer 10

The interface separating two adjoining grains having different orientations

Question 11

Define grain growth

Answer 11

The increase in average grain size of a polycrystalline material. Most materials need a temperature increase for this

Question 12

What happens to an atomic structure when force is applied to it?

Answer 12

The Atomic bonds stretch and the attractive forces between the atoms opposes the applied force. When the stress is removed and if the metal has not yielded the inter atomic forces pull the metal back to its original shape

Question 13

What are the two categories of nucleation and what are they?

Answer 13

Homogenous - the nuclei for solidification is provided by the liquid melt

Heterogenous - the nucleation occurs in a liquid on the surface of its container.

Question 14

Define polymorphism

Answer 14

The existence of two or more different crystal structures for a substance ( generally an elemental solid)

Question 15

Define allotropy

Answer 15

Allotropes have the same chemical properties but different physical properties

Question 16

Name four categories of imperfections/ defects in materials

Answer 16

Point defects
Interfacial
Linear
Bulk or volume

Question 17

Define an impurity point defect

Answer 17

Substitutional - the solute or impurity atoms replace the host atoms

Question 18

What four factors determine the degree of the solvent atoms in the sub alloy

Answer 18

Atomic size factor
Crystal structure
Electronegativity
Valences

Question 19

Define atomic size factor

Answer 19

One shouldn’t be bigger than the other or it’ll be fucked

Question 20

Define Crystal structure in retaliation to imperfections in metal

Answer 20

Crystal structures for metals of both atom types must be the same

Question 21

Define electronegativety

Answer 21

The more positive one element is compared to the other more negative one then the likelihood that they will form an intermetallic compound will increase rather than it forming a substitutional solid solution

Question 22

Define valences

Answer 22

A metal with a higher valency will tend to dissolve a metal with a lower valency

Question 23

Describe a dislocation in a material

Answer 23

A dislocation is a linear defect around which some of the atoms are mis aligned.

Question 24

What is a twin boundary

Answer 24

A grain boundary where there is specific mirror lattice symmetry

Question 25

What are the three types of microscopy?

Answer 25

Optical
Electronic ( scanning and transmission)
Scanning probe ( scanning, tunneling, atomic force)

Question 26

Describe optical microscopy

Answer 26

The effect of etching into the surface of a metal to uncover th grain structure underneath

Question 27

Describe a scanning electron microscope

Answer 27

A SEM produces an image by firing an electron beam at the surface of a specimen which are reflected to form an image

Question 28

Describe a transmission electron microscope

Answer 28

An image is produced by a beam of electrons that pass through a specimen

Question 29

Describe a scanning probe microscope

Answer 29

An SPM uses a very sharp probe Rasta scans across the specimen surface which form a topographical graph on a nano scale