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What is the slope of the stress-strain diagram from O to P known as?
What is the slope of the stress-strain diagram from O to P known as?
The yield point indicates the maximum stress a material can withstand before rupture.
The yield point indicates the maximum stress a material can withstand before rupture.
False
What is the region in the stress-strain diagram from point O to P called?
What is the region in the stress-strain diagram from point O to P called?
elastic range
The ______ strength is defined as the maximum strength of the material at rupture.
The ______ strength is defined as the maximum strength of the material at rupture.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Which of the following processes is NOT part of bulk processes?
Which of the following processes is NOT part of bulk processes?
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Sheet metalworking is characterized by high surface area to volume ratio.
Sheet metalworking is characterized by high surface area to volume ratio.
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Name one type of operation that can be classified as machining.
Name one type of operation that can be classified as machining.
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The property of a material that allows it to return to its original size and shape after a load stops acting on it is called __________.
The property of a material that allows it to return to its original size and shape after a load stops acting on it is called __________.
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Match the following fabrication methods with their descriptions:
Match the following fabrication methods with their descriptions:
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Which machining method uses a wheel composed of abrasive particles?
Which machining method uses a wheel composed of abrasive particles?
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Ductility refers to a material's ability to fracture under stress.
Ductility refers to a material's ability to fracture under stress.
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What is the role of hardening processes in machining?
What is the role of hardening processes in machining?
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Which of the following is an example of step-reaction polymerization?
Which of the following is an example of step-reaction polymerization?
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High-density polyethylene (HDPE) has a high degree of branching compared to low-density polyethylene (LDPE).
High-density polyethylene (HDPE) has a high degree of branching compared to low-density polyethylene (LDPE).
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What is a copolymer?
What is a copolymer?
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A polymer is considered polar if it has __________ and __________ poles.
A polymer is considered polar if it has __________ and __________ poles.
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Match the type of polymer with its description:
Match the type of polymer with its description:
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Which factor does NOT affect the polarity of a polymer?
Which factor does NOT affect the polarity of a polymer?
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Low-density polyethylene (LDPE) has a higher melting point than high-density polyethylene (HDPE).
Low-density polyethylene (LDPE) has a higher melting point than high-density polyethylene (HDPE).
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What is the purpose of copolymerization?
What is the purpose of copolymerization?
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What is a common property of zinc?
What is a common property of zinc?
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Lead can be easily cut with a knife.
Lead can be easily cut with a knife.
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What is the melting point of zinc?
What is the melting point of zinc?
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Lead has a boiling point of __________.
Lead has a boiling point of __________.
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Match the following uses of zinc and lead with their appropriate applications.
Match the following uses of zinc and lead with their appropriate applications.
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Which of the following methods is used for creating small intricate parts such as jewelry and machine components?
Which of the following methods is used for creating small intricate parts such as jewelry and machine components?
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Expendable mold casting allows the mold to be reused multiple times.
Expendable mold casting allows the mold to be reused multiple times.
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What is the elastic limit in the context of the stress-strain diagram?
What is the elastic limit in the context of the stress-strain diagram?
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The yield point is the maximum stress that a material can endure before it fractures.
The yield point is the maximum stress that a material can endure before it fractures.
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What is the primary characteristic of Powdered Metallurgy?
What is the primary characteristic of Powdered Metallurgy?
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In metal forming, raw metal is usually manipulated in __________ form.
In metal forming, raw metal is usually manipulated in __________ form.
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What does Young's Modulus represent in a stress-strain diagram?
What does Young's Modulus represent in a stress-strain diagram?
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Match the following metal manufacturing processes with their appropriate description:
Match the following metal manufacturing processes with their appropriate description:
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The region in a stress-strain diagram where permanent deformation occurs is called the __________ range.
The region in a stress-strain diagram where permanent deformation occurs is called the __________ range.
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Match the following terms with their corresponding definitions:
Match the following terms with their corresponding definitions:
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Which process is NOT suitable for high-strength applications?
Which process is NOT suitable for high-strength applications?
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Deformation processes involve applying stresses that exceed the yield strength of metal.
Deformation processes involve applying stresses that exceed the yield strength of metal.
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What is the main advantage of metal forming compared to casting?
What is the main advantage of metal forming compared to casting?
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What defines tensile strength in materials?
What defines tensile strength in materials?
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Compressive stress results in an increase in the material's length.
Compressive stress results in an increase in the material's length.
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What is the term used to describe the ratio of change in length to the original length in materials?
What is the term used to describe the ratio of change in length to the original length in materials?
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The stress that results from forces applied parallel to the resisting area is known as __________.
The stress that results from forces applied parallel to the resisting area is known as __________.
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Which type of material is characterized by having relatively large tensile strains before rupture?
Which type of material is characterized by having relatively large tensile strains before rupture?
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Brittle materials can experience relatively large strains before reaching their point of rupture.
Brittle materials can experience relatively large strains before reaching their point of rupture.
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What is the typical unit of measure used for stress in materials?
What is the typical unit of measure used for stress in materials?
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Which of the following is a characteristic of and the reason for the formation of intermediate phases in alloys?
Which of the following is a characteristic of and the reason for the formation of intermediate phases in alloys?
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Ferrous metals do not contain iron as a primary constituent.
Ferrous metals do not contain iron as a primary constituent.
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What is the carbon content range for Grey Cast Iron?
What is the carbon content range for Grey Cast Iron?
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Metals generally exhibit good __________ conductivity, making them ideal for electrical applications.
Metals generally exhibit good __________ conductivity, making them ideal for electrical applications.
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Match the type of cast iron with its property:
Match the type of cast iron with its property:
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Which of the following is NOT a characteristic of Cast Iron?
Which of the following is NOT a characteristic of Cast Iron?
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What are the three classifications of Ferrous metals?
What are the three classifications of Ferrous metals?
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Non-ferrous metals contain significant amounts of iron.
Non-ferrous metals contain significant amounts of iron.
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Which of the following polymers are examples of step-reaction polymerization?
Which of the following polymers are examples of step-reaction polymerization?
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High-density polyethylene (HDPE) is a result of highly branched molecular chains.
High-density polyethylene (HDPE) is a result of highly branched molecular chains.
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What type of polymer is created by linking only one type of monomer?
What type of polymer is created by linking only one type of monomer?
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Polymers can be classified based on their branching degree, with _______ indicating higher density due to closely packed molecules.
Polymers can be classified based on their branching degree, with _______ indicating higher density due to closely packed molecules.
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Match the following types of polymers with their definitions:
Match the following types of polymers with their definitions:
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Polarity in materials influences properties like melting point and solubility.
Polarity in materials influences properties like melting point and solubility.
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What type of stress results from a tensile force applied to a material?
What type of stress results from a tensile force applied to a material?
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Which crystal system has atoms arranged at the corners of the cube with another atom at the center?
Which crystal system has atoms arranged at the corners of the cube with another atom at the center?
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In a Face-Centered Cubic (FCC) structure, there are 2 atoms in one unit cell.
In a Face-Centered Cubic (FCC) structure, there are 2 atoms in one unit cell.
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Brittle materials can undergo large strains before breaking.
Brittle materials can undergo large strains before breaking.
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What is the packing density of the Simple Cubic (SC) structure?
What is the packing density of the Simple Cubic (SC) structure?
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What is the term used for the ratio of change in length to the original length in materials?
What is the term used for the ratio of change in length to the original length in materials?
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The property of __________ describes how atoms are arranged within a unit cell.
The property of __________ describes how atoms are arranged within a unit cell.
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Which of the following describes a ductile material?
Which of the following describes a ductile material?
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Match the following metallic crystal structures with their characteristic:
Match the following metallic crystal structures with their characteristic:
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Which of the following is a characteristic of the arrangement in a Face-Centered Cubic (FCC) structure?
Which of the following is a characteristic of the arrangement in a Face-Centered Cubic (FCC) structure?
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Which term refers to the internal stress caused by compressive forces?
Which term refers to the internal stress caused by compressive forces?
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Polonium is an example of a metal that forms a Simple Cubic (SC) structure.
Polonium is an example of a metal that forms a Simple Cubic (SC) structure.
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Normal stress can be classified as either tensile stress or compressive stress.
Normal stress can be classified as either tensile stress or compressive stress.
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How many types of crystal systems can be defined based on length and orientation?
How many types of crystal systems can be defined based on length and orientation?
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What defines a unit cell in the context of crystal structure?
What defines a unit cell in the context of crystal structure?
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Lattice parameters are represented by only three dimensions.
Lattice parameters are represented by only three dimensions.
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Name two areas of science that focus on the study of materials.
Name two areas of science that focus on the study of materials.
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The arrangement of atoms in crystalline solids affects their __________.
The arrangement of atoms in crystalline solids affects their __________.
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Which statement about crystalline solids is true?
Which statement about crystalline solids is true?
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Gold was the first metal to be used by mankind.
Gold was the first metal to be used by mankind.
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What are the six lattice parameters in crystal structures?
What are the six lattice parameters in crystal structures?
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Which of the following metals is NOT an example of a body-centered cubic (BCC) structure?
Which of the following metals is NOT an example of a body-centered cubic (BCC) structure?
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The hexagonal closed-pack (HCP) structure contains 6 atoms per unit cell.
The hexagonal closed-pack (HCP) structure contains 6 atoms per unit cell.
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What notation is used to represent crystallographic directions?
What notation is used to represent crystallographic directions?
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The two lattice parameters of the hexagonal closed-pack (HCP) structure are 'a' and __________.
The two lattice parameters of the hexagonal closed-pack (HCP) structure are 'a' and __________.
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Match the following crystal structures with their examples:
Match the following crystal structures with their examples:
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Which equation represents the relationship between the cube edge length 'a' and the atomic radius 'R'?
Which equation represents the relationship between the cube edge length 'a' and the atomic radius 'R'?
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A line or vector in crystallography is termed a 'crystallographic coordinate'.
A line or vector in crystallography is termed a 'crystallographic coordinate'.
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Describe how to convert crystallographic directions from four notation to three notation in hexagonal crystals.
Describe how to convert crystallographic directions from four notation to three notation in hexagonal crystals.
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What is the primary reason for extracting carbon from cast iron to produce Malleable Cast Iron?
What is the primary reason for extracting carbon from cast iron to produce Malleable Cast Iron?
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Wrought Iron has a carbon content of 2.0%.
Wrought Iron has a carbon content of 2.0%.
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What are two types of cast iron mentioned in the content?
What are two types of cast iron mentioned in the content?
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______ iron is an almost pure form of iron with high resistance to corrosion.
______ iron is an almost pure form of iron with high resistance to corrosion.
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Match the following types of steel with their carbon content:
Match the following types of steel with their carbon content:
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What is the coordination number for Face-Centered Cubic (FCC) and Hexagonal Close-Packed (HCP) structures?
What is the coordination number for Face-Centered Cubic (FCC) and Hexagonal Close-Packed (HCP) structures?
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The Atomic Packing Factor (APF) for Simple Cubic (SC) structures is 0.68.
The Atomic Packing Factor (APF) for Simple Cubic (SC) structures is 0.68.
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What is the primary purpose of alloying metals?
What is the primary purpose of alloying metals?
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The _____ density refers to the number of atoms per unit length along a specific direction.
The _____ density refers to the number of atoms per unit length along a specific direction.
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What type of solid solution involves solvent atoms being replaced by dissolved elements?
What type of solid solution involves solvent atoms being replaced by dissolved elements?
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Match the following with their definitions:
Match the following with their definitions:
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All metals have a non-crystalline structure.
All metals have a non-crystalline structure.
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What are the two classifications of alloys?
What are the two classifications of alloys?
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Study Notes
Introduction to Engineering Materials
- Engineering materials are crucial for survival and daily life.
- Gold was the first metal used, followed by copper.
- Areas of science focusing on materials include Engineering Materials, Material Science, and Materials Engineering.
Basic Concepts of Crystal Structure
- Properties of crystalline solids depend on the crystal structure.
- The manner in which atoms, ions, or molecules are spatially arranged influences these properties.
- A space lattice or lattice is a periodic arrangement of points in space.
- A lattice point represents each atom.
- A lattice array is the arrangement of lattice points.
- Lattice space is the space covered by lattice points.
- A unit cell is a tiny block formed by arrangements of small groups of atoms.
- It represents the symmetry of the crystal structure.
- The unit cell can be defined as a small repeat entity, the basic structural unit, or the building block of the crystal structure.
- Lattice parameters (a, b, c, α, β, γ) describe the dimensions and angles of the unit cell.
- These parameters are typically on the order of a few Angstroms (Å) or 0.1 nanometers.
- The orientation and equality of these parameters define the 7 crystal systems (cubic, hexagonal, tetragonal, rhombohedral, orthorhombic, monoclinic, and triclinic).
Bravais Lattices
- There are 14 types of crystal systems.
- These systems include properties of centering.
- Types of centering include Face-Centered, Body-Centered, and Base-Centered.
Metallic Crystal Structures
-
Simple Cubic (SC):
- Three mutually perpendicular axes pass through one corner of the unit cell.
- Each corner is occupied by one atom.
- Polonium is the only element that has this structure.
- Packing density is relatively low.
-
Body-Centered Cubic (BCC):
- Atoms are arranged at the corners of the cube, with an additional atom at the center.
- Examples include alpha iron, chromium, tungsten, tantalum, and molybdenum.
-
Face-Centered Cubic (FCC):
- Atoms are arranged at the corners and centers of each face of the unit cell.
- Atoms are assumed to touch along face diagonals.
- Examples include aluminum, copper, gold, lead, silver, and nickel.
Hexagonal Closed-Pack (HCP)
- The unit cell is formed with top and bottom planes of 7 atoms, and a half-hexagon in between.
- Two lattice parameters (a and c) define the basal and height parameters.
- Six atoms are present in one unit cell.
- Zinc, lithium, magnesium, and beryllium are examples.
Crystallographic Directions
- Directions in a crystal are represented by the coordinates (x, y, z) of a vector passing through the origin.
- Notation: [uvw].
- Conversion between four-notation and three-notation systems is explained for hexagonal crystals.
Properties of Crystals:
- Coordination Number: The number of nearest neighbor atoms or ions surrounding an atom or ion.
-
Atomic Packing Factor (APF or Packing Efficiency): Ratio of volume of atoms in a unit cell to volume of unit cell.
- SC: ~ 0.52
- FCC and HCP: ~ 0.74
- BCC: ~ 0.68
- Planar Density: Density of atomic packing on a particular plane.
- Linear Density: Number of atoms per unit length along a particular direction.
Metals
- Employed in various engineering purposes and requirements.
- Iron is the most popular metal in engineering.
- All metals have a crystalline structure.
Alloys
- Alloys are mixtures or compounds of two or more elements, at least one of which is metallic.
- Alloying enhances properties such as strength and hardness.
- Alloys can be classified as solid solutions or intermediate phases.
- Substitutional Solid Solution: atoms of a solvent element are replaced in its unit cell by atoms of a dissolved element.
- Interstitial Solid Solution: atoms of a dissolved element fit into vacant spaces between base metal atoms in the lattice structure.
- Intermediate Phases: have limits to solubility of one element in another. They have intermediate chemical composition and different crystalline structures.
Importance of Metals
- High stiffness and strength (can be alloyed for high rigidity)
- Hardness (capacity to absorb energy better than other materials)
- Good electrical conductivity
- Good thermal conductivity
- Cost (steel is competitive with other engineering materials)
Metals Used in Manufacturing Process
- Cast Metal: Starting form is a casting.
- Wrought Metal: Metal that has been worked or can be worked after casting.
- Powdered Metal: Starting form is small powders for conversion into parts using powder metallurgy techniques.
Classification of Metals
- Ferrous Metals: Contain iron as the main constituent. Classified as cast iron, wrought iron, and steel.
- Non-ferrous Metals: Practically do not contain iron.
Cast Iron (C.I)
- Carbon content ranges from 2 to 4.23%.
- Formed by melting pig iron with coke and lime stone.
- Types of Cast Iron include:
- Gray Cast Iron: 3% carbon content, soft, melts easily used in cylinders, pistons
- White Cast Iron: 2.0-2.5% carbon content, hard, unworkable in machines.
- Chilled Cast Iron: 3.3% carbon content, hard on the surface, soft inside, used in rail car wheels, dies, sprockets
- Malleable Cast Iron: 2.3% carbon content, malleable
- Toughened Cast Iron: cast iron obtained by melting cast iron with wrought iron scrap.
Wrought Iron
- Almost pure iron (0.15% carbon).
- Manufacturing stages include refining, puddling, shingling, and rolling.
- Properties: soft at white stage, ductile, malleable, tough, 1500°C melting point, and resistant to corrosion.
Steel
- Iron alloy with up to 2.0% carbon.
- Types of steel include low carbon (mild), medium carbon, and high carbon steel.
Alloy Steel
- Steel to which other elements are added to obtain special properties.
- Examples include chromium steel, cobalt steel, manganese steel, tungsten steel, vanadium steel, and nickel steel.
Polymers
- Polymers are engineering materials of very high molecular weight.
- Created by joining monomer units.
- Used in food packaging, clothing, home furnishing, transportation, medical devices, and other applications.
- Types of Polymerization include:
- Chain-reaction: monomers bond to form polymers.
- Step-reaction: monomers bond through release of small molecules.
Polymer Structure and Properties
- Crystallinity: High ordered structure (crystalline) verses random structure (amorphous).
- Molecular Weight Distribution: Wider distribution easier to melt, narrower distribution harder to melt.
- Viscoelasticity: Exhibits both viscous (flow) and elastic (return to original shape) properties.
Nanomaterials
- Nanotechnology is the science, engineering, and technology conducted at the nanoscale (1-100 nanometers).
- Nanomaterials are nano-scale particles, tubes, rods, or fibers. They have wide range in applications (health, electronics, cosmetics, textiles, information technology and environmental protection).
-
Manufacturing methods:
- Top-down: reducing large pieces of material to nanoscale.
- Bottom-up: building up from atomic- and molecular-scale components.
-
New processes:
- Chemical vapor deposition
- Molecular beam epitaxy
- Atomic layer epitaxy
- Nanoimprint lithography
- Roll-to-roll processing
- Self-assembly
- Potential effects: Include potential interactions with biological systems (e.g. brain diseases) and potential environmental impacts.
Mechanical Properties of Materials
- Strength: Capacity of material to withstand breaking, bowing, or deformation.
- Elasticity: Ability of a material to return to its original shape and size after stress is removed.
- Plasticity: Ability to deform permanently without fracture.
- Ductility: Ability to deform and draw into wires.
- Tensile Strength: Ability to deform without fracture when pulled or stretched.
- Stress: Strength of a material per unit area.
- Normal Stress: Tensile or compressive stress.
- Shearing Stress: Force applied parallel to the resisting area.
- Bearing Stress: Contact pressure between bodies.
- Simple Strain: Ratio of change in length to original length.
- Stress-Strain Diagram: Graphical representation of stress and strain relationship.
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Description
Test your knowledge on material science concepts and machining processes. This quiz covers the stress-strain diagram, types of strength, and machining methods. Additionally, you'll explore key properties of materials and fabrication techniques essential in engineering.