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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.
Generation of a Magnetic Field - Vacuum
Heat Capacity
There is no perfect material?
Work Hardening
2. 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.
Luminescence examples
Brittle Fracture
Stress Intensity values
Heat Capacity
3. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Why materials fail in service
4 Types of Magnetism
Superconductivity
Fatigue
4. 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
Intergranular Fracture
Thermal Stresses
Refraction
Paramagnetic Materials
5. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Bending tests
Pure Semiconductors: Conductivity vs. T
Metals: Resistivity vs. T - Impurities
Thermal Stresses
6. If a material has ________ - then the field generated by those moments must be added to the induced field.
Engineering Fracture Performance
Internal magnetic moments
Transgranular Fracture
Meissner Effect
7. Defines the ability of a material to resist fracture even when a flaw exists - Directly depends on size of flaw and material properties - K(ic) is a materials constant
Linewidth
Specific Heat
Oxidation
Stress Intensity Factor
8. # of thermally generated electrons = # of holes (broken bonds)
Impact energy
Intrinsic Semiconductors
Large Hardness
Impact - Toughness
9. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Internal magnetic moments
Response to a Magnetic Field
IC Devices: P-N Rectifying Junction
Color
10. Different orientation of cleavage planes in grains.
Valence band
Why fracture surfaces have faceted texture
Large Hardness
Electrical Conduction
11. For a metal - there is no ______ - only reflection
Relative Permeability
Transparent
Opacifiers
Refraction
12. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
To improve fatigue life
Hard Magnetic Materials
Holloman Equation
Thermal expansion
13. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Ductile Fracture
Incident Light
Superconductivity
Magnetic Storage
14. Emitted light is in phase
Thermal expansion
How an LCD works
Meissner Effect
Coherent
15. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Ductile Fracture
Luminescence
High impact energy
Metals: Resistivity vs. T - Impurities
16. Increase temperature - increase in interatomic separation - thermal expansion
Meissner Effect
To improve fatigue life
Coherent
Thermal Expansion: Asymmetric curve
17. Stress concentration at a crack tips
Meissner Effect
Reflection of Light for Metals
Griffith Crack Model
What do magnetic moments arise from?
18. Typical loading conditions are _____ enough to break all inter-atomic bonds
Not severe
Incident Light
Incoherent
Magnetic Storage Media Types
19. The ability of a material to be rapidly cooled and not fracture
Large Hardness
Thermal Shock Resistance
Domains in Ferromagnetic & Ferrimagnetic Materials
Generation of a Magnetic Field - Within a Solid Material
20. 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.
Brittle Ceramics
Incoherent
Impact - Toughness
Reflectance of Non-Metals
21. 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
Energy States: Insulators and Semiconductors
Iron-Silicon Alloy in Transformer Cores
IC Devices: P-N Rectifying Junction
Reflectance of Non-Metals
22. Because of ionic & covalent-type bonding.
Domains in Ferromagnetic & Ferrimagnetic Materials
Thermal Expansion: Symmetric curve
Why do ceramics have larger bonding energy?
Superconductivity
23. 1. Tensile (opening) 2. Sliding 3. Tearing
The three modes of crack surface displacement
Stress Intensity values
Ductile-to-Brittle Transition
Lithography
24. High toughness; material resists crack propagation.
Reflectance of Non-Metals
Ductile Fracture
The three modes of crack surface displacement
High impact energy
25. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Hysteresis and Permanent Magnetization
Magnetic Storage Media Types
Hard Magnetic Materials
Conduction & Electron Transport
26. Width of smallest feature obtainable on Si surface
Not severe
Opacity
Brittle Fracture
Linewidth
27. 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.
Impact energy
Scattering
Magnetic Storage
Extrinsic Semiconductors
28. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
IC Devices: P-N Rectifying Junction
Extrinsic Semiconductors
The three modes of crack surface displacement
Magnetic Storage Media Types
29. Another optical property - Depends on the wavelength of the visible spectrum.
Color
Liquid Crystal Displays (LCD's)
Magnetic Storage Media Types
M is known as what?
30. 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
Thermal Conductivity
To improve fatigue life
Refraction
Critical Properties of Superconductive Materials
31. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)
Two kinds of Reflection
Soft Magnetic Materials
Domains in Ferromagnetic & Ferrimagnetic Materials
Specific Heat
32. 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
Hysteresis and Permanent Magnetization
Incident Light
Shear and Tensile Stress
Response to a Magnetic Field
33. 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
Not severe
Oxidation
4 Types of Magnetism
Valence band
34. 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 - Vacuum
Yield and Reliability
Force Decomposition
35. Elastic means reversible! This is not a permanent deformation.
Elastic Deformation
Relative Permeability
Impact energy
The three modes of crack surface displacement
36. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Luminescence
Liquid Crystal Displays (LCD's)
Heat Capacity from an Atomic Prospective
Incoherent
37. ...occurs in bcc metals but not in fcc metals.
Soft Magnetic Materials
Domains in Ferromagnetic & Ferrimagnetic Materials
Engineering Fracture Performance
Where does DBTT occur?
38. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
What do magnetic moments arise from?
Holloman Equation
Influence of Temperature on Magnetic Behavior
Valence band
39. Diffuse image
Superconductivity
Coherent
Translucent
To improve fatigue life
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
Reflection of Light for Metals
Brittle Ceramics
Thermal Expansion: Symmetric curve
Impact - Toughness
41. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.
Heat Capacity from an Atomic Prospective
Engineering Fracture Performance
High impact energy
Heat Capacity
42. Sigma=ln(li/lo)
Generation of a Magnetic Field - Within a Solid Material
True Stress
True Strain
Elastic Deformation
43. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Metals: Resistivity vs. T - Impurities
Where does DBTT occur?
Work Hardening
Refraction
44. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
True Strain
Superconductivity
Energy States: Insulators and Semiconductors
Coefficient of Thermal Expansion
45. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
What do magnetic moments arise from?
Why materials fail in service
True Stress
Energy States: Insulators and Semiconductors
46. 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
Metallization
Yield and Reliability
Engineering Fracture Performance
Refraction
47. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.
Iron-Silicon Alloy in Transformer Cores
Metallization
HB (Brinell Hardness)
Shear and Tensile Stress
48. These materials are relatively unaffected by magnetic fields.
Force Decomposition
Soft Magnetic Materials
IC Devices: P-N Rectifying Junction
Diamagnetic Materials
49. 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
Scattering
Paramagnetic Materials
Shear and Tensile Stress
50. 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
Brittle Fracture
Modulus of Rupture (MOR)
How an LCD works
Superconductivity