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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. The ability of a material to absorb heat - Quantitatively: The energy required to produce a unit rise in temperature for one mole of a material.
Superconductivity
Liquid Crystal Displays (LCD's)
Heat Capacity
The three modes of crack surface displacement
2. These materials are relatively unaffected by magnetic fields.
Ductile Materials
Diamagnetic Materials
Generation of a Magnetic Field - Within a Solid Material
Specific Heat
3. 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
Scattering
Yield and Reliability
Coherent
How to gage the extent of plastic deformation
4. Ability to transmit a clear image - The image is clear.
Transparent
Thermal Expansion: Asymmetric curve
Stress Intensity values
Meissner Effect
5. 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
Brittle Materials
Magnetic Storage Media Types
Extrinsic Semiconductors
Critical Properties of Superconductive Materials
6. 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.
Critical Properties of Superconductive Materials
Iron-Silicon Alloy in Transformer Cores
Reflectance of Non-Metals
Why materials fail in service
7. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
Refraction
Intergranular Fracture
HB (Brinell Hardness)
Superconductivity
8. 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
Soft Magnetic Materials
Refraction
Opacity
Large Hardness
9. Because of ionic & covalent-type bonding.
Why do ceramics have larger bonding energy?
Elastic Deformation
Brittle Ceramics
Not severe
10. Typical loading conditions are _____ enough to break all inter-atomic bonds
True Strain
Linewidth
M is known as what?
Not severe
11. 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.
Opaque
What do magnetic moments arise from?
Scattering
Translucent
12. Resistance to plastic deformation of cracking in compression - and better wear properties.
Large Hardness
Hard Magnetic Materials
Why materials fail in service
Meissner Effect
13. 1. Ductility- % elongation - % reduction in area - may be of use in metal forming operations (e.g. - stretch forming). This is convenient for mechanical testing - but not very meaningful for most deformation processing. 2. Toughness- Area beneath str
How to gage the extent of plastic deformation
Rockwell
Specific Heat
Two ways to measure heat capacity
14. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.
Extrinsic Semiconductors
Opaque
Meissner Effect
Electromigration
15. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Bending tests
Brittle Ceramics
Refraction
Force Decomposition
16. Increase temperature - increase in interatomic separation - thermal expansion
Metallization
Internal magnetic moments
Thermal Expansion: Asymmetric curve
Insulators
17. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.
Superconductivity
Force Decomposition
The three modes of crack surface displacement
Two ways to measure heat capacity
18. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Thermal Shock Resistance
Thermal expansion
Pure Semiconductors: Conductivity vs. T
How an LCD works
19. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Metals: Resistivity vs. T - Impurities
Force Decomposition
The Transistor
Fatigue
20. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)
Film Deposition
Two ways to measure heat capacity
Fourier's Law
Generation of a Magnetic Field - Within a Solid Material
21. 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
Thermal Expansion: Symmetric curve
4 Types of Magnetism
Plastic Deformation (Metals)
Why do ceramics have larger bonding energy?
22. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Griffith Crack Model
Shear and Tensile Stress
Conduction & Electron Transport
Incident Light
23. 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
Thermal Stresses
Yield and Reliability
Oxidation
Heat Capacity from an Atomic Prospective
24. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Generation of a Magnetic Field - Within a Solid Material
Refraction
Electrical Conduction
Impact energy
25. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Intrinsic Semiconductors
Hard Magnetic Materials
Reflectance of Non-Metals
Thermal Shock Resistance
26. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Shear and Tensile Stress
Incident Light
IC Devices: P-N Rectifying Junction
Ductile Materials
27. Undergo extensive plastic deformation prior to failure.
Translucent
To improve fatigue life
Ductile Materials
Paramagnetic Materials
28. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Soft Magnetic Materials
Coherent
Modulus of Rupture (MOR)
Thermal Stresses
29. 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
Reflectance of Non-Metals
Hysteresis and Permanent Magnetization
Translucent
How an LCD works
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."
Opacifiers
Charpy or Izod test
Work Hardening
Linewidth
31. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Dependence of Heat Capacity on Temperature
HB (Brinell Hardness)
Extrinsic Semiconductors
What do magnetic moments arise from?
32. 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.
Opaque
How an LCD works
Hardness
Etching
33. 1. Tensile (opening) 2. Sliding 3. Tearing
The three modes of crack surface displacement
Impact energy
Why fracture surfaces have faceted texture
Why materials fail in service
34. ...occurs in bcc metals but not in fcc metals.
Thermal Expansion: Symmetric curve
To improve fatigue life
Where does DBTT occur?
Generation of a Magnetic Field - Vacuum
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
Opaque
The three modes of crack surface displacement
Superconductivity
36. 1. Stress-strain behavior is not usually determined via tensile tests 2. Material fails before it yields 3. Bend/flexure tests are often used instead.
Impact energy
Brittle Ceramics
The three modes of crack surface displacement
Etching
37. 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
Stress Intensity Factor
Why do ceramics have larger bonding energy?
Stages of Failure: Ductile Fracture
38. 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
Color
Thermal Conductivity
Slip Bands
Stress Intensity Factor
39. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Energy States: Insulators and Semiconductors
Thermal Expansion: Symmetric curve
Conduction & Electron Transport
Fourier's Law
40. 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
Thermal Stresses
Reflection of Light for Metals
Transparent
Thermal Expansion: Asymmetric curve
41. 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
Shear and Tensile Stress
Relative Permeability
The Transistor
Response to a Magnetic Field
42. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
Brittle Fracture
Extrinsic Semiconductors
Two kinds of Reflection
True Strain
43. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
Etching
Stages of Failure: Ductile Fracture
What do magnetic moments arise from?
Heat Capacity from an Atomic Prospective
44. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Heat Capacity from an Atomic Prospective
Refraction
Force Decomposition
Domains in Ferromagnetic & Ferrimagnetic Materials
45. Diffuse image
Translucent
Engineering Fracture Performance
Brittle Fracture
Elastic Deformation
46. High toughness; material resists crack propagation.
Impact - Toughness
Modulus of Rupture (MOR)
High impact energy
Linewidth
47. Without passing a current a continually varying magnetic field will cause a current to flow
Hysteresis and Permanent Magnetization
Impact - Toughness
Diamagnetic Materials
Response to a Magnetic Field
48. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.
Metallization
Liquid Crystal Displays (LCD's)
To improve fatigue life
Lithography
49. Width of smallest feature obtainable on Si surface
Fourier's Law
Linewidth
Color
Why materials fail in service
50. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)
Response to a Magnetic Field
Work Hardening
Magnetic Storage Media Types
Rockwell