Manageable Upload Flashcards
What is toughness?
The ability of material to absorb energy without fracturing. Area under stress-strain graph.
What is stiffness?
Higher elastic modulus.
What is ultimate tensile strength?
Maximum stress.
What are the three types of lattice structures?
FCC, BCC, HCP
Rate lattice structures in terms of atomic packing factor.
HCP=FCC>BCC
What are the 0-dimensional defects?
Point defects
What are the 1-dimensional defects?
linear defects, dislocations
What are the 2-dimensional defects?
Interfacial defects, stacking faults, grain boundaries
What are the 3-dimensional defects?
Precipitates, Impurities, Voids
What are dislocations?
Dislocations are line defects in metals and ceramics. They are generated by deforming a crystalline
material.
What is ductility?
Ductility is the ability to undergo substantial plastic deformation before failure.
Rate the lattice structures in terms of ductility.
FCC > BCC > HCP
What are the three strengthening mechanisms for metals and ceramics?
- Solid Solution Strengthening
- Grain Size Reduction
- Strain Hardening
How do strengthening mechanisms strengthen a material?
They hinder the movement of dislocations.
What is solid solution strengthening?
Foreign atoms dissolved in material.
What is grain size rediction?
Increasing number of grain boundaries.
What is strain hardening?
Introducing new dislocations.
What is a single crystal?
Perfect periodic arrangement of atoms throughout specimen with same orientation.
What is a polycrystalline material?
Many crystals separated by grain boundaries.
What are the advantages of larger grain size? (3)
- Higher melting temperature
- Higher elastic modulus
- Higher creep resistance
What are advantages of smaller grain size? (2)
- Higher creep
- Better toughness and strength
What is a phase diagram?
Phase diagrams in metals represent the physical states (microstructure) and transformation as a function of its alloy and temperature.
Draw the Iron-Iron Carbide Phase Diagram.
check with lecture
What carbon content defines iron?
C < 0.008%
What carbon content defines steel?
0.009% < C < 2.14%
What carbon content defines cast iron?
2.14% < C < 6.7%
Draw 0% - 2% Iron-Iron Carbide diagram
Check with lecture.
What is pearlite?
Alternating layers of ferrite and cementite.
What is the process for heat treatment?
Heat, hold, cool
Why is heat treatment performed?
To improve desired qualities such as strength, toughness, hardness, and ductility
Fill out the annealing areas in the iron-carbide diagram!
Check with lecture
What is hardening?
Very fast cooling up to quench for non-equilibrium microstructure.
What is annealing?
Slow cooling rates for fully diffused equilibrium maintaining microstructure.
What are the most common alloying elements for steel? (8)
- Carbon
- Silicon
- Manganese
- Phosphorous
- Sulfur
- Chromium
- Nickel
- Molybdenum
What Carbon content does low carbon steel have?
< 0.25%
What Carbon content does medium carbon steel have?
0.25% < C < 0.6%
What Carbon content does high-carbon steel have?
0.6% < C < 1.4%
What is Stainless steel?
Steel with atleast 11% Chromium content.
What is a quality of Stainless Steel?
Resistant to corrosion in a variety of environments.
What are the four types of plastics?
Elastomers, Amorphous Thermoplastics, Semi-Crystalline Thermoplastics, Thermosets
What are the four types of copolymers?
Alternating, statistical, block, and graft.
Draw the structure of the four plastic types.
Check with lecture
Draw the shear modulus-temperature graph for the four plastic types.
Check with lecture.
Draw tensile strength-youngs modulus graph comparing plastics with other materials.
Check with lecture.
What are the three methods of polymer syntheses?
- Polymerization
- Polycondensation
- Polyaddition
What are the three types of polymerization?
Radical, Ionic, Coordinative
What are some examples of polymers formed by polymerization?
- Polyvinyl Chloride
- Polyethylene
- Polystyrene
What are some properties of thermosets? (7)
- Few plastics are thermosets
- Cross-linked polymer with 3-D network structure
- Covalent bonds linking the chains
- Stiff and brittle
- Temperature resistant
- Non-meltable
- Heat loosens bonds
What are the typical components of thermosets?
- Resin
- Curing Agent
- Accelerator
- Hardener
What are the advantages of thermosets? (6)
- Low processing temperature
- Good compression properties
- Resistant to creep
- Good fatigue properties
- Formable into complex shapes
- Highly resistant to solvents
What are the disadvantages of thermosets? (6)
- Long processing time
- Long cure
- Low ductility
- Low fracture toughness
- Low impact resistance
- Absorb moisture
How do thermosets behave differently at their decomposition temperature?
They don’t melt, they decompose because of their close-meshed network.
What kind of molecules are needed to create thermosets?
- Molecules with at least three cross linking possibilities
- Molecules with three or more functional bondings
What are three high performance thermosets?
- Poly Methacryl Imide (PMI)
- Bismaleimides (BI)
- Polyimides (PI)
What are three technical thermosets?
- Epoxy Resins (EP)
- Phenolic Resins (PR)
- Silicone Resins (SI)
What are four mass plastics?
- Urea Resin (UR)
- Vinyl Ester Resin (VE)
- Polyurethan (PUR)
- Melamine Resin (MF)
What are some processes for thermoset part production? (8)
- Hand lay-up
- Fiber resin spraying
- Braiding
- Vacuum bag process
- Autoclave process
- Winding process
- Pultrusion
- Resin Transfer Molding (RTM)
What are the three processes for semi-finished thermoset part production?
- Prepregs
- SMC
- BMC
Why cant thermosets be recycled?
They cannot be melted.
Draw cold curing diagram for thermosets.
Check with lecture.
Draw TTT-Diagram for thermosets.
Check with lecture.
What are the three types of curing for thermosets?
Warm, cold, light.
What two curing types require an accelerator?
Cold and light curing.
Name five standard thermoplastics.
- Polyethylene (PE)
- Polypropylene (PP)
- Polystyrene (PS)
- Polyvinyl Chloride (PVC)
- Polyethylene terephthalate (PET)
Name six engineering thermoplastics.
- Polyoxymethylene (POM)
- Polyamide (PA)
- Polymethylmethacrylate (PMMA)
- Polyurethane (PUR)
- Polybutylene terephthalate (PBT)
Name four high performance thermoplastics.
- Polyether ether ketone (PEEK)
- Polyether sulfone (PES)
- Polyimide (PI)
- Polytetrafluoroethylene (PTFE)
What are two types of thermoplastics?
Amorphous and semi-crystalline.
What are the three types of polyethylene?
- PE-HD
- PE-LD
- PE-LLD
What are the three types of polystyrene?
Isotactic, atactic, sinotactic
What are the manufacturing processes for primary shaping of thermoplastics? (7)
- Extrusion
- Injection Molding
- Blow Molding
- Compression Molding
- Calendaring
- Spinning
- Casting
What is the forming process for thermoplastics?
Thermoforming.
What are the five thermoplastics used in aerospace?
- Polyether ether ketone (PEEK)
- Polyphenylene sulfide (PPS)
- Polysulfone (PSU)
- Polyetherimide (PEI)
- Polycarbonate
What are some disadvantages of thermoplastics in aerospace? (4)
- High viscosity
- High processing
temperature - Poor creep resistance
- High processing pressure
Why are thermoplastics used in aerospace? (7)
- Non-reacting
- Rapid processing
- High ductility
- High fracture toughness
- High impact resistance
- Absorb little moisture
- Can be recycled
What is the main purpose of thermoplastics in aerospace?
As structural adhesive.
What are the types of casting?
- Sand Casting
- Investment Casting
- Lost Foam Casting
- Mold Casting
- Die Casting
What are the Casting defects?
- Cavities
- Cold Shuts
- Warpage
- Stress Cracks
- Undersize
- Inclusions
- Gas Porosity
What are some methods for primary shaping of polymers?
- Extrusion
- Injection Molding
- Reinforced Polymers
What are some forging methods?
- Open die forging
- Impression die forging
- Flashless forging
- Closed die impression
- Coining
- Press and Hammer
What are the types of rolling?
- Longitudinal
- Traverse
- Pierce
- Flat
- Profile
- Thread
What are the types of sheet bending?
- V- die
- Wiping die
- U-die
- Tube bending
What are some tube bending defects?
- Flattening
- Wrinkling
- Outer wall thinning
- Springback
What are some deep drawing defects?
Flange wrinkeling
- Wall wrinkeling
- Tearing
- Earing
- Surface scratchers
What are some sheet forming processes?
- Deep Drawing
- Stretch Forming
- Spinning
- Shot peen forming
What are some forming processes for plastics and composites?
- Vaccum forming
- Diaphram forming
- Thermoforming
- Blow molding
What are the three means of joining?
- Form closure
- Force closure
- Material closure
What are some exaples of joining by force closure?
Notching
Folding
Clinching
Wrapping
Tube reduction
Folding
Lock forming
Crimping
Wrapping
What are the types of turning?
- Facing
- Chamfering
- Threading
- Roll turning
- Contour turning
- Form turning
What are the types of drilling?
- Rotary
- Spot face
- Tapping
- Profiling
- Form
- Deep hole
What are the types of milling?
- Face
- Circular
- Spiral
- Roll
- Profile
- Form
What are the types of cleaning?
- Wet
- Blast
- Mechanical
- Thermal
- Special
What are some wet cleaning processes?
- Splash cleaning
- Ultrasonic cleaning
What is a blast cleaning processes ?
- Snow-Jet cleaning
What is a mechanical cleaning process?
Brushing
What is a thermal cleaning process?
Laser beam cleaning
What is a special cleaning process?
Plasma cleaning
