Week 1 Flashcards
Define microstructures
The fine structure that can be made visible and examined with a microscope
What are micro constituents
An identifiable element of the microstructure
Can microconstituents consist of more than one phase
Yes
Microstructure structure or micro constituent
Structure
Microstructure on micro constituent?
Constituent
Name this
Substitutional foreign atom
Name this
Interstitial foreign atom
Name this
Vacancy
Name this
Unit cell of alpha-iron
Name this
Edge dislocation
Name this
Screw dislocation
Name this
Incoherent precipitates
Name this
Continuous grain boundaries
Name this
Coherent precipitates
Name this
Grain boundary
Name this
Grain boundary
Name this
High melting point inclusion
Name this
Slip lines
List the 5 things on the bonding graph and where they are
Stress strain graph: what does it look like for a guitars string
(What type of steel is a guitars string)
Blue curve
(Martensitic steel)
Stress strain curve: what does it look like for spheroidized steel
(2 qualities of spheroidized steel)
Red curve
(Very week but ductile
List the 4 elements of the materials paradigm and where they are
Describe cold worked and recovered grains compared to regular grains
What type of bonds do polymers have
Covalent bonds
What type of bonds are covalent bonds
Secondary bonds
Polymers: ____ melting point, 3 other qualities
Point
Insulators
Weak
Impact resistance
What allows us to distinguish between classes of materials
Atomic bonding
What are the 2 things here
Big blue: ion core
Pink: sea of valence electrons
Ionic bonds: between _____ and ______ ions, electrons not ______ but ______,
non-______, strong and _______
Positive and negative
Shared but transferred
Non directional
Inflexible
What type of bonding is this
Ionic bonds
Covalent bonds: electrons are _____, strong and ________, comparable __________, ________
Shared
Inflexible
Electronegatitivies
Directional
Which type of bonds are generally the strongest
Covalent
What type of bonding is this
Covalent (electrons are shared)
Metallic bonds: “the ____ of electrons”, non-_______, variable ______
Sea
Non directional
Strength
What type of bonding is this
Metallic
4 properties of metals
Conductive
Malleable/ductile
Opaque
Good tension and compression
Are metals good or bad in tension and compression
Good
What are the weakest type of bonds
Secondary bonds
What type of interactions do secondary bonds have (main 3)
And what are these classified as
London dispersion, hydrogen, van der waal
(Classified as dipole-dipole interactions)
What type of bonding is this
Van Der Waals
What type of bonding is this
Hydrogen bonding
What type of bonding is this
Secondary bonds
Define the materials paradigm
(2 points)
The conceptual framework used to understand, design, and develop materials with specific properties and functions
Involves the study of the structure, composition, and processing of materials to tailor their properties to various applications
Name the three classes of materials
Metals
Polymers
Ceramics
Should properties vary with the amount of material sampled
No
Define a property
A characteristic of something that can be measured or observed and provided info about its behaviour, composition, or quality
What deformation process is this
Forging
What deformation process is this
Direct extrusion
What deformation process is this
Indirect extrusion
List the 4 modes of loading
Tension
Compression
Bending
Shear
What happens to atoms in tension and compression
Tension: atoms pulled apart
Compression: pushing atoms together
What is bending a combination of
Tension and compression
What what happens to atoms during shear
Atoms moving against each other
What mode of loading is this
Bending
What mode of loading is this
Shear
“If each sample has a different cross section, how do you tell which is strongest” relates to what calculation
Engineering stress
What does “different cross sectional areas”, Ao, look like
Which calculation answers the question “how do we tell how much a sample has deformed”
Engineering strain
What calculation relates to compression
Compressive stress
What does a stress-strain curve generally look like
(4 things)
-elastic deformation
-yield strength
-UTS (plastic deformation)
-Slope (Young’s modulus)
Plastic and elastic deformation: state which is recoverable and which isn’t
Elastic: recoverable
Plastic: non-recoverable
Why is elastic deformation RECOVERABLE
Because you’re stretching atoms
Define yield strength
The stress at which a material begins physically deforming and WON’T return to its original shape when an applied stress is removed
Define UTS
The maximum stress a material can withstand BEFORE breaking
Where is fillet radii on a dog bone
What is the purpose of fillet radii
-distributes stress by reducing concentrations at the junction of two intersection components
(Smooth transition to minimize crack and failures)
Describe where the “reduced section” and “gauge length” are on a dog bone
What is the reduced section of a dog bone and what is it used for
The areas of the body ne where it narrows due to deformation
Used for calculating true stress as the material undergoes deformation
What is the gauge length of a dog bone and what is it used for
The designated region of the bone where strain is measured during tensile testing
Used for strain measurements
Describe the three stages of what bonds look like during the process of elastic deformation
Good to look at
Plastic deformation: onset is at _____ _____ on stress strain curve
Yield point
Stress strain curve: engineering stress rises until the ______ is reached
UTS
Stress strain curve: WHERE DOES NECKING OCCUR
Necking occurs at the UTS
How to draw the yield offset
Draw a line parallel to the LINEAR elastic region offset by a strain of 0.2%
Why do we draw the yield offset
(And what are we calculating when we do this)
Since yield tends to be gradual this is how we determine yield stress
Bruh
When is a sample brittle and when is it ductile on a stress strain curve
What question does the %EL formula answer
How did the LENGTH of the sample change during deformation
What question does the %RA answer
How did the CROSS-SECTIONAL AREA of the sample change
What does a true stress strain curve look like, a corrected one, and an engineering one
“If a sample expands along the z axis, what happens along the x and y axis?”
Can be answered by which formula
Poison’s ratio
Theoretically, what is Poisson’s ratio for isotropic materials
b=0.25
What are isotopic materials
Materials with uniform properties in ALL directions
(Physical and mechanical characteristics are the same regardless of which direction they’re measured)
3 examples of isotopic materials
Polycrystalline metals
Glass
Rubber
In practice, what is the range for Poisson’s ratio for metals
v= 0.25-0.35
Does this show brittle ceramics, ductile metals, or ductile polymers
Brittle ceramics
Where something fractures is also called the _____ _____
Elastic limit
Does this show brittle ceramics,ductile metals, or ductile polymers
Ductile metals
Does this show brittle ceramics,ductile metals, or ductile polymers
Ductile polymers
What happens to atoms during plastic deformation
They undergo permanent rearrangement
(Facilitated by the motion and multiplication of dislocations)
Describe each line on the stress strain drive in terms of toughness: (and give material class for lines 1 and 3)
-steep linear line
-less steep line, parabolic down
-least steep, almost parallel to x axis
1) smaller toughness (ceramics)
2) larger toughness
3) smaller toughness (unreinforced polymers)
