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Test your basic knowledge |
Engineering Materials
Start Test
Study First
Subject
:
engineering
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. These materials are relatively unaffected by magnetic fields.
Diamagnetic Materials
Luminescence examples
What do magnetic moments arise from?
Linewidth
2. A high index of refraction (n value) allows for multiple internal reactions.
Heat Capacity
Soft Magnetic Materials
Sparkle of Diamonds
Griffith Crack Model
3. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.
Where does DBTT occur?
Elastic Deformation
How to gage the extent of plastic deformation
Meissner Effect
4. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
M is known as what?
Opacity
Ductile-to-Brittle Transition
Charpy or Izod test
5. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Opacifiers
Extrinsic Semiconductors
Superconductivity
The Transistor
6. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Thermal Expansion: Asymmetric curve
Large Hardness
Incident Light
Thermal expansion
7. Measures Hardness - No major sample damage - Each scales runs to 130 but only useful in range 20-100 - Minor load is 10 kg - Major load: 60 kg (diamond) - 100 kg (1/16 in. ball) - 150 kg (diamond)
Critical Properties of Superconductive Materials
4 Types of Magnetism
Hysteresis and Permanent Magnetization
Rockwell
8. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Thermal Stresses
Domains in Ferromagnetic & Ferrimagnetic Materials
Heat Capacity
Force Decomposition
9. Cracks propagate along grain boundaries.
Dependence of Heat Capacity on Temperature
Intergranular Fracture
Superconductivity
Heat Capacity
10. 1. Yield = ratio of functional chips to total # of chips - Most yield loss during wafer processing - b/c of complex 2. Reliability - No device has infinite lifetime. Statistical methods to predict expected lifetime - Failure mechanisms: Diffusion reg
Stages of Failure: Ductile Fracture
Superconductivity
Reflectance of Non-Metals
Yield and Reliability
11. Stress concentration at a crack tips
Griffith Crack Model
IC Devices: P-N Rectifying Junction
Critical Properties of Superconductive Materials
Paramagnetic Materials
12. Increase temperature - no increase in interatomic separation - no thermal expansion
Thermal Expansion: Symmetric curve
LASER
Rockwell
Hysteresis and Permanent Magnetization
13. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Liquid Crystal Displays (LCD's)
Relative Permeability
Energy States: Insulators and Semiconductors
HB (Brinell Hardness)
14. A three terminal device that acts like a simple "on-off" switch. (the basis of Integrated Circuits (IC) technology - used in computers - cell phones - automotive control - etc) - If voltage (potential) applied to the "gate" - current flows between th
The Transistor
Heat Capacity
Impact - Toughness
Slip Bands
15. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION
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16. - The emission of light from a substance due to the absorption of energy. (Could be radiation - mechanical - or chemical energy. Could also be energetic particles.) - Traps and activator levels are produced by impurity additions to the material - Whe
Stress Intensity Factor
Slip Bands
Dependence of Heat Capacity on Temperature
Luminescence
17. - Metals that exhibit high ductility - exhibit high toughness. Ceramics are very strong - but have low ductility and low toughness - Polymers are very ductile but are not generally very strong in shear (compared to metals and ceramics). They have low
Thermal Stresses
Liquid Crystal Displays (LCD's)
Stress Intensity values
HB (Brinell Hardness)
18. Ability to transmit a clear image - The image is clear.
Stress Intensity Factor
Reflection of Light for Metals
Transparent
True Strain
19. There is always some statistical distribution of flaws or defects.
What do magnetic moments arise from?
Ductile Materials
Electrical Conduction
There is no perfect material?
20. Elastic means reversible! This is not a permanent deformation.
How an LCD works
Holloman Equation
Elastic Deformation
Dependence of Heat Capacity on Temperature
21. 1. Fluorescent Lamp - tungstate or silicate coating on inside of tube emits white light due to UV light generated inside the tube. 2. TV screen - emits light as electron beam is scanned back and forth.
Metals: Resistivity vs. T - Impurities
Why materials fail in service
Thermal Stresses
Luminescence examples
22. Different orientation of cleavage planes in grains.
Sparkle of Diamonds
Thermal Expansion: Asymmetric curve
Metallization
Why fracture surfaces have faceted texture
23. Occurs at a single pore or other solid by refraction n = 1 for pore (air) n > 1 for the solid - n ~ 1.5 for glass - Scattering effect is maximized by pore/particle size within 400-700 nm range - Reason for Opacity in ceramics - glasses and polymers.
Intrinsic Semiconductors
Response to a Magnetic Field
Scattering
LASER
24. Width of smallest feature obtainable on Si surface
M is known as what?
Linewidth
IC Devices: P-N Rectifying Junction
Brittle Materials
25. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
Ductile Materials
HB (Brinell Hardness)
Why materials fail in service
Hardness
26. A measure of the ease with which a B field can be induced inside a material.
Relative Permeability
Opacifiers
True Strain
4 Types of Magnetism
27. The size of the material changes with a change in temperature - polymers have the largest values
Yield and Reliability
Film Deposition
Thermal Stresses
Coefficient of Thermal Expansion
28. The magnetic hysteresis phenomenon: Stage 1: Initial (unmagnetized state) Stage 2: Apply H - align domains Stage 3: Remove H - alignment remains => Permanent magnet Stage 4: Coercivity - Hc negative H needed to demagnitize Stage 5: Apply -H - align d
There is no perfect material?
Diamagnetic Materials
Color
Hysteresis and Permanent Magnetization
29. Transmitted light distorts electron clouds - The velocity of light in a material is lower than in a vacuum - Adding large ions to glass decreases the speed of light in the glass - Light can be "bent" (or refracted) as it passes through a transparent
Intrinsic Semiconductors
Diamagnetic Materials
Sparkle of Diamonds
Refraction
30. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Metals: Resistivity vs. T - Impurities
IC Devices: P-N Rectifying Junction
Brittle Materials
Coefficient of Thermal Expansion
31. A parallel-plate capacitor involves an insulator - or dielectric - between two metal electrodes. The charge density buildup at the capacitor surface is related to the dielectric constant of the material.
Refraction
Insulators
Specific Heat
Luminescence
32. 1. Diamagnetic (Xm ~ 10^-5) - small and negative magnetic susceptibilities 2. Paramagnetic (Xm ~ 10^-4) - small and positive magnetic susceptibilities 3. Ferromagnetic - large magnetic susceptibilities 4. Ferrimagnetic (Xm as large as 10^6) - large m
Translucent
4 Types of Magnetism
High impact energy
Griffith Crack Model
33. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))
Heat Capacity from an Atomic Prospective
Metals: Resistivity vs. T - Impurities
True Stress
Luminescence
34. Measures impact energy 1. Strike a notched sample with an anvil 2. Measure how far the anvil travels following impact 3. Distance traveled is related to energy required to break the sample 4. Very high rate of loading. Makes materials more "brittle."
Charpy or Izod test
Fatigue
Brittle Ceramics
Where does DBTT occur?
35. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.
To improve fatigue life
Intrinsic Semiconductors
Transparent
Superconductivity
36. 1. Tensile (opening) 2. Sliding 3. Tearing
The three modes of crack surface displacement
True Stress
Hard Magnetic Materials
Brittle Materials
37. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Superconductivity
How an LCD works
Engineering Fracture Performance
Two kinds of Reflection
38. The ability of a material to be rapidly cooled and not fracture
Paramagnetic Materials
Internal magnetic moments
Slip Bands
Thermal Shock Resistance
39. Not ALL the light is refracted - SOME is reflected. Materials with a high index of refraction also have high reflectance - High R is bad for lens applications - since this leads to undesirable light losses or interference.
Two kinds of Reflection
Reflectance of Non-Metals
Scattering
Fourier's Law
40. Without passing a current a continually varying magnetic field will cause a current to flow
Response to a Magnetic Field
Insulators
Fatigue
Generation of a Magnetic Field - Vacuum
41. Transformer cores require soft magnetic materials - which are easily magnetized and de-magnetized - and have high electrical resistivity - Energy losses in transformers could be minimized if their cores were fabricated such that the easy magnetizatio
Linewidth
Coherent
Fourier's Law
Iron-Silicon Alloy in Transformer Cores
42. Resistance to plastic deformation of cracking in compression - and better wear properties.
Large Hardness
Impact energy
Magnetic Storage
Two kinds of Reflection
43. Diffuse image
Translucent
Conduction & Electron Transport
Fourier's Law
Impact - Toughness
44. Plastic means permanent! When a small load is applied - bonds stretch & planes shear. Then when the load is no longer applied - the planes are still sheared.
Critical Properties of Superconductive Materials
Hard Magnetic Materials
Relative Permeability
Plastic Deformation (Metals)
45. Digitalized data in the form of electrical signals are transferred to and recorded digitally on a magnetic medium (tape or disk) - This transference is accomplished by a recording system that consists of a read/write head - "write" or record data by
Linewidth
Relative Permeability
Influence of Temperature on Magnetic Behavior
Magnetic Storage
46. Wet: isotropic - under cut Dry: ansiotropic - directional
Etching
Brittle Materials
Slip Bands
Magnetic Storage Media Types
47. 1. Tc= critical temperature- if T>Tc not superconducting 2. Jc= critical current density - if J>Jc not superconducting 3. Hc= critical magnetic field - if H > Hc not superconducting
Metallization
Coefficient of Thermal Expansion
There is no perfect material?
Critical Properties of Superconductive Materials
48. These materials are "attracted" to magnetic fields.
Thermal Shock Resistance
The Transistor
Thermal expansion
Paramagnetic Materials
49. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Conduction & Electron Transport
True Strain
Two kinds of Reflection
How an LCD works
50. For a metal - there is no ______ - only reflection
The Transistor
Relative Permeability
Hardness
Refraction