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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. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Extrinsic Semiconductors
Modulus of Rupture (MOR)
Engineering Fracture Performance
Brittle Ceramics
2. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Stress Intensity Factor
Hardness
Energy States: Insulators and Semiconductors
Ductile Materials
3. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture
Extrinsic Semiconductors
Dependence of Heat Capacity on Temperature
Stages of Failure: Ductile Fracture
Luminescence
4. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.
Brittle Ceramics
Coherent
Lithography
Bending tests
5. Undergo little or no plastic deformation.
Translucent
Lithography
Brittle Materials
Heat Capacity from an Atomic Prospective
6. ...occurs in bcc metals but not in fcc metals.
Sparkle of Diamonds
M is known as what?
Yield and Reliability
Where does DBTT occur?
7. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.
Heat Capacity from an Atomic Prospective
Two ways to measure heat capacity
Response to a Magnetic Field
Domains in Ferromagnetic & Ferrimagnetic Materials
8. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Impact - Toughness
Where does DBTT occur?
Modulus of Rupture (MOR)
Engineering Fracture Performance
9. Liquid polymer at room T - sandwiched between two sheets of glass - coated with transparent - electrically conductive film. - Character forming letters/ numbers etched on the face - Voltage applied disrupts the orientation of the rod- shaped molecule
Etching
Force Decomposition
How an LCD works
Intergranular Fracture
10. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Scattering
Brittle Ceramics
IC Devices: P-N Rectifying Junction
Brittle Fracture
11. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Metals: Resistivity vs. T - Impurities
Valence band
Electromigration
Why materials fail in service
12. For a metal - there is no ______ - only reflection
Refraction
Holloman Equation
Linewidth
Brittle Fracture
13. A high index of refraction (n value) allows for multiple internal reactions.
Transparent
Generation of a Magnetic Field - Vacuum
Impact - Toughness
Sparkle of Diamonds
14. 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.
Pure Semiconductors: Conductivity vs. T
IC Devices: P-N Rectifying Junction
Hard Magnetic Materials
Plastic Deformation (Metals)
15. There is always some statistical distribution of flaws or defects.
How an LCD works
Transgranular Fracture
Specific Heat
There is no perfect material?
16. Typical loading conditions are _____ enough to break all inter-atomic bonds
Internal magnetic moments
Soft Magnetic Materials
Not severe
M is known as what?
17. Undergo extensive plastic deformation prior to failure.
IC Devices: P-N Rectifying Junction
Thermal Shock Resistance
What do magnetic moments arise from?
Ductile Materials
18. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Hardness
The Transistor
Thermal Shock Resistance
Generation of a Magnetic Field - Within a Solid Material
19. 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.
Insulators
Generation of a Magnetic Field - Within a Solid Material
Why materials fail in service
Opacifiers
20. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Incident Light
Coefficient of Thermal Expansion
Thermal Conductivity
Ductile-to-Brittle Transition
21. Hardness is the resistance of a material to deformation by indentation - Useful in quality control - Hardness can provide a qualitative assessment of strength - Hardness cannot be used to quantitatively infer strength or ductility.
Hardness
Holloman Equation
Insulators
Valence band
22. 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
Two ways to measure heat capacity
The Transistor
Iron-Silicon Alloy in Transformer Cores
Stress Intensity Factor
23. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
Linewidth
Large Hardness
Thermal Stresses
Why materials fail in service
24. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Soft Magnetic Materials
LASER
Critical Properties of Superconductive Materials
Modulus of Rupture (MOR)
25. Increase temperature - no increase in interatomic separation - no thermal expansion
Generation of a Magnetic Field - Vacuum
Internal magnetic moments
Refraction
Thermal Expansion: Symmetric curve
26. The size of the material changes with a change in temperature - polymers have the largest values
Coefficient of Thermal Expansion
Color
Stress Intensity Factor
Film Deposition
27. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.
Refraction
Reflectance of Non-Metals
Coefficient of Thermal Expansion
Heat Capacity from an Atomic Prospective
28. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Modulus of Rupture (MOR)
Fatigue
Brittle Materials
Specific Heat
29. Second phase particles with n > glass.
Griffith Crack Model
Opacifiers
Generation of a Magnetic Field - Within a Solid Material
Superconductivity
30. 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."
Stress Intensity Factor
Superconductivity
Diamagnetic Materials
Charpy or Izod test
31. Diffuse image
Translucent
Liquid Crystal Displays (LCD's)
Influence of Temperature on Magnetic Behavior
Thermal Expansion: Asymmetric curve
32. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.
Translucent
Engineering Fracture Performance
To improve fatigue life
Impact energy
33. Wet: isotropic - under cut Dry: ansiotropic - directional
Thermal Expansion: Asymmetric curve
Hardness
Etching
Diamagnetic Materials
34. The ability of a material to transport heat - Atomic Perspective: Atomic vibrations and free electrons in hotter regions transport energy to cooler regions - Metals have the largest values
Incident Light
Thermal Conductivity
Refraction
Force Decomposition
35. Degree of opacity depends on size and number of particles - Opacity of metals is the result of conduction electrons absorbing photons in the visible range.
Opacity
Why materials fail in service
Thermal Stresses
Heat Capacity
36. High toughness; material resists crack propagation.
True Stress
Opacifiers
Intergranular Fracture
High impact energy
37. Width of smallest feature obtainable on Si surface
Linewidth
Soft Magnetic Materials
Ductile-to-Brittle Transition
Intrinsic Semiconductors
38. 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
Electromigration
LASER
Liquid Crystal Displays (LCD's)
Hysteresis and Permanent Magnetization
39. Created by current through a coil N= total number of turns L= length of turns (m) I= current (ampere) H= applied magnetic field (ampere-turns/m) Bo= magnetic flux density in a vacuum (tesla)
Generation of a Magnetic Field - Vacuum
Fatigue
Griffith Crack Model
Energy States: Insulators and Semiconductors
40. 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.
LASER
Luminescence examples
Energy States: Insulators and Semiconductors
Impact energy
41. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.
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42. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
Modulus of Rupture (MOR)
Valence band
Ductile-to-Brittle Transition
Dependence of Heat Capacity on Temperature
43. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)
4 Types of Magnetism
Thermal Expansion: Symmetric curve
Thermal Shock Resistance
Magnetic Storage Media Types
44. Materials change size when temperature is changed
Domains in Ferromagnetic & Ferrimagnetic Materials
Thermal expansion
Critical Properties of Superconductive Materials
M is known as what?
45. Sigma=ln(li/lo)
Yield and Reliability
Extrinsic Semiconductors
True Strain
Ductile Materials
46. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Why fracture surfaces have faceted texture
Conduction & Electron Transport
Yield and Reliability
The three modes of crack surface displacement
47. A measure of the ease with which a B field can be induced inside a material.
Lithography
Relative Permeability
To improve fatigue life
Energy States: Insulators and Semiconductors
48. Growth of an oxide layer by the reaction of oxygen with the substrate - Provides dopant masking and device isolation - IC technology uses 1. Thermal grown oxidation (dry) 2. Wet Oxidation 3. Selective Oxidation
Influence of Temperature on Magnetic Behavior
Oxidation
The Transistor
Sparkle of Diamonds
49. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Stress Intensity values
Brittle Materials
Brittle Fracture
Incoherent
50. Reflectiviy is between 0.90 and 0.95 - Metal surfaces appear shiny - Most of absorbed light is reflected at the same wavelength (NO REFRACTION) - Small fraction of light may be absorbed - Color of reflected light depends on wavelength distribution of
Reflection of Light for Metals
Ductile Fracture
Conduction & Electron Transport
Coherent