Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
3 defined groups/categories of Metallurgy? - (ANSWER)- Extractive
- Mechanical
- Physical
Define 'Extractive' Metallurgy. - (ANSWER)- The study of extraction and purification of metals from their
ores. This includes a stepped process which can utilize Pyrometallurgy, Hydrometallurgy or
Electrometallurgy
Define Pyrometallurgy: - (ANSWER)- Melting the ore in a furnace to release the metal
Define Hydrometallurgy: - (ANSWER)- Dissolving the metal from the ore and recovering it as a powder
Define Electrometallurgy: - (ANSWER)- Dissolving the metal from the ore with the use of electricity,
plate the metal out of solution
What is Mechanical Metallurgy? - (ANSWER)- The study of the techniques and mechanical forces that
shape and make finished forms of metal
- The study of the effects of stress, time and temperature
What is Physical Metallurgy? - (ANSWER)- The study of the structure of metals - property of metals are
intimately related to their structures
- The physical metallurgy - or structure of a metal - can be changed by modifying chemical composition,
alloys and heat treatments
General characteristics of 'Metals'? - (ANSWER)- Good conductors of heat and electricity
- Generally malleable and ductile
- Occur naturally in ores in the form of chemical compounds such as sulphides or oxides
What are Noble Metals? - (ANSWER)- A metal that resists chemical action and does not corrode or
oxidize, and is not easily attacked by acids
,Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
Metals can exist in 3 common physical states depending on what? - (ANSWER)Temperature and
pressure
Describe 'latent heat of fusion' in relation to metals. - (ANSWER)- Het energy is added until temperature
no longer increases and the cohesive bonds holding the individual atoms together break. This causes the
metal to melt.
The main concern with metallurgy and industry is...? - (ANSWER)- The complexity of the solid-to liquid-
to solid phase changes metals go through as they are refined
- The chemical and physical properties exhibited by them during these transitions
Define 'Unit Cells' in relation to the atomic structure of metals. - (ANSWER)- When a metal changes state
from molten to solid, the rigid atomic structure of the atoms settles in 1 of 3 possible configurations:
1) Face-centered cubic (FCC) unit cells
2) Body-centered cubic (BCC) unit cells
3) Close Packed Hexagonal (CPH) unit cells
Face-centered Cubic (FCC) unit cells? - (ANSWER)- 14 atoms make up the FCC cell
- Properties include: high ductility, low shear, low tensile strength, but good thermal and electrical
conductivity
Define Ductility: - (ANSWER)- A measure of a metals ability to undergo significant plastic deformation
before rupture, which may be expressed as elongation or percent area reduction from a tensile test.
- Often characterized by a materials ability to be stretched into a wire
Define Malleability: - (ANSWER)- A materials ability to deform under compressive stress; often
characterized by a materials ability to form a thin sheet by hammering or rolling - without fracture.
Both ductility and malleability are aspects of a materials...? - (ANSWER)- Plasticity: the extent to which a
solid material can be plastically deformed without fracture
,Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
- The plasticity is dependant on temperature and pressure
Ductility and malleability are not always coextensive. True or False? - (ANSWER)True. Gold is both
ductile and malleable while Lead has a very low ductility but high malleability.
What is Shear Strength? - (ANSWER)- The strength of a material or component against the type of yield
or structural failure when the component fails in shear.
What is Shear Load? - (ANSWER)- A force that tends to produce a sliding failure on a material along a
plane that is parallel to the direction of the force.
Metals that have FCC unit cell structures in the solid state? - (ANSWER)- Gold, aluminum, silver, lead,
nickel, gamma iron (iron between temperatures 910 - 1390 deg.C)
# of atoms contained in a BCC structure? - (ANSWER)9 atoms total
Characteristics of metals with the Body-centered cubic structure? - (ANSWER)- High strength
- Low ductility
- Very resistant to shear deformities
Examples of BCC metals? - (ANSWER)Chromium, tungsten, molybdenum, vanadium, alpha iron (solid
state iron below 910 deg.C) and delta iron (iron above 1390 deg.C)
How many atoms make up a Close-packed hexagonal structure? - (ANSWER)17 atoms total
Characteristics of CPH structured unit cells? - (ANSWER)Intermediate strength and Intermediate ductility
Materials that possess CPH unit cell structures? - (ANSWER)Zinc, magnesium, cadmium, titanium
, Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
When molten metal cools and solidifies, what action do unit cells take? - (ANSWER)- Unit cells become
packed together to form 3 dimensional crystals that occupy a space lattice.
Further growth of these crystals form dendrites (evergreen tree looking crystals)
Properties of materials with small grain size? - (ANSWER)- High tensile strength
- Highly ductile
Properties of materials with large grain size? - (ANSWER)- High creep/deformation resistance under
constant loading
- More prone to cracking
Shear strength of metals is primarily determined by the type of Unit Cell Structure exhibited. True or
False? - (ANSWER)True.
1) HIGH ATOM PACKED DENSITY FCC structures are very ductile (easy to elongate) with a low shear
strength - Ex.) Lead.
2) LOW ATOM PACKED DENSITY BCC structures have high hardness and a high shear strength. Ex.) Iron
Opposite of metal hardness is...? - (ANSWER)- A hard metal is does not possess TOUGHNESS.
- Hardness: resistance to deformation
What is Polymorphism and what does it have to do with metals? - (ANSWER)- The ability of a metal to
change its unit cell structure through varying temperature ranges.
- Most metals exhibit this property; most important for the study of iron.
What is the allotropy of Iron? - (ANSWER)- The change in atomic cell structure dependant on
temperature
- Various physical forms of metals can affect their: melting point, hardness, metal solubility, and alloying
chemistry.
Properties of pure Iron? - (ANSWER)- Relatively soft
Solutions
3 defined groups/categories of Metallurgy? - (ANSWER)- Extractive
- Mechanical
- Physical
Define 'Extractive' Metallurgy. - (ANSWER)- The study of extraction and purification of metals from their
ores. This includes a stepped process which can utilize Pyrometallurgy, Hydrometallurgy or
Electrometallurgy
Define Pyrometallurgy: - (ANSWER)- Melting the ore in a furnace to release the metal
Define Hydrometallurgy: - (ANSWER)- Dissolving the metal from the ore and recovering it as a powder
Define Electrometallurgy: - (ANSWER)- Dissolving the metal from the ore with the use of electricity,
plate the metal out of solution
What is Mechanical Metallurgy? - (ANSWER)- The study of the techniques and mechanical forces that
shape and make finished forms of metal
- The study of the effects of stress, time and temperature
What is Physical Metallurgy? - (ANSWER)- The study of the structure of metals - property of metals are
intimately related to their structures
- The physical metallurgy - or structure of a metal - can be changed by modifying chemical composition,
alloys and heat treatments
General characteristics of 'Metals'? - (ANSWER)- Good conductors of heat and electricity
- Generally malleable and ductile
- Occur naturally in ores in the form of chemical compounds such as sulphides or oxides
What are Noble Metals? - (ANSWER)- A metal that resists chemical action and does not corrode or
oxidize, and is not easily attacked by acids
,Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
Metals can exist in 3 common physical states depending on what? - (ANSWER)Temperature and
pressure
Describe 'latent heat of fusion' in relation to metals. - (ANSWER)- Het energy is added until temperature
no longer increases and the cohesive bonds holding the individual atoms together break. This causes the
metal to melt.
The main concern with metallurgy and industry is...? - (ANSWER)- The complexity of the solid-to liquid-
to solid phase changes metals go through as they are refined
- The chemical and physical properties exhibited by them during these transitions
Define 'Unit Cells' in relation to the atomic structure of metals. - (ANSWER)- When a metal changes state
from molten to solid, the rigid atomic structure of the atoms settles in 1 of 3 possible configurations:
1) Face-centered cubic (FCC) unit cells
2) Body-centered cubic (BCC) unit cells
3) Close Packed Hexagonal (CPH) unit cells
Face-centered Cubic (FCC) unit cells? - (ANSWER)- 14 atoms make up the FCC cell
- Properties include: high ductility, low shear, low tensile strength, but good thermal and electrical
conductivity
Define Ductility: - (ANSWER)- A measure of a metals ability to undergo significant plastic deformation
before rupture, which may be expressed as elongation or percent area reduction from a tensile test.
- Often characterized by a materials ability to be stretched into a wire
Define Malleability: - (ANSWER)- A materials ability to deform under compressive stress; often
characterized by a materials ability to form a thin sheet by hammering or rolling - without fracture.
Both ductility and malleability are aspects of a materials...? - (ANSWER)- Plasticity: the extent to which a
solid material can be plastically deformed without fracture
,Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
- The plasticity is dependant on temperature and pressure
Ductility and malleability are not always coextensive. True or False? - (ANSWER)True. Gold is both
ductile and malleable while Lead has a very low ductility but high malleability.
What is Shear Strength? - (ANSWER)- The strength of a material or component against the type of yield
or structural failure when the component fails in shear.
What is Shear Load? - (ANSWER)- A force that tends to produce a sliding failure on a material along a
plane that is parallel to the direction of the force.
Metals that have FCC unit cell structures in the solid state? - (ANSWER)- Gold, aluminum, silver, lead,
nickel, gamma iron (iron between temperatures 910 - 1390 deg.C)
# of atoms contained in a BCC structure? - (ANSWER)9 atoms total
Characteristics of metals with the Body-centered cubic structure? - (ANSWER)- High strength
- Low ductility
- Very resistant to shear deformities
Examples of BCC metals? - (ANSWER)Chromium, tungsten, molybdenum, vanadium, alpha iron (solid
state iron below 910 deg.C) and delta iron (iron above 1390 deg.C)
How many atoms make up a Close-packed hexagonal structure? - (ANSWER)17 atoms total
Characteristics of CPH structured unit cells? - (ANSWER)Intermediate strength and Intermediate ductility
Materials that possess CPH unit cell structures? - (ANSWER)Zinc, magnesium, cadmium, titanium
, Power Engineering 2A2 - Part 1 (Thermodynamics, Metallurgy, Welding) Questions With Complete
Solutions
When molten metal cools and solidifies, what action do unit cells take? - (ANSWER)- Unit cells become
packed together to form 3 dimensional crystals that occupy a space lattice.
Further growth of these crystals form dendrites (evergreen tree looking crystals)
Properties of materials with small grain size? - (ANSWER)- High tensile strength
- Highly ductile
Properties of materials with large grain size? - (ANSWER)- High creep/deformation resistance under
constant loading
- More prone to cracking
Shear strength of metals is primarily determined by the type of Unit Cell Structure exhibited. True or
False? - (ANSWER)True.
1) HIGH ATOM PACKED DENSITY FCC structures are very ductile (easy to elongate) with a low shear
strength - Ex.) Lead.
2) LOW ATOM PACKED DENSITY BCC structures have high hardness and a high shear strength. Ex.) Iron
Opposite of metal hardness is...? - (ANSWER)- A hard metal is does not possess TOUGHNESS.
- Hardness: resistance to deformation
What is Polymorphism and what does it have to do with metals? - (ANSWER)- The ability of a metal to
change its unit cell structure through varying temperature ranges.
- Most metals exhibit this property; most important for the study of iron.
What is the allotropy of Iron? - (ANSWER)- The change in atomic cell structure dependant on
temperature
- Various physical forms of metals can affect their: melting point, hardness, metal solubility, and alloying
chemistry.
Properties of pure Iron? - (ANSWER)- Relatively soft
