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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. 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
Magnetic Storage
Scattering
Diamagnetic Materials
Reflection of Light for Metals
2. 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
Extrinsic Semiconductors
Stages of Failure: Ductile Fracture
Griffith Crack Model
How to gage the extent of plastic deformation
3. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)
Superconductivity
Stress Intensity Factor
Magnetic Storage Media Types
Impact - Toughness
4. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Brittle Materials
Diamagnetic Materials
Metals: Resistivity vs. T - Impurities
Dependence of Heat Capacity on Temperature
5. 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
Rockwell
Coefficient of Thermal Expansion
Hardness
6. Elastic means reversible! This is not a permanent deformation.
Plastic Deformation (Metals)
Elastic Deformation
Magnetic Storage Media Types
Heat Capacity
7. These materials are relatively unaffected by magnetic fields.
To improve fatigue life
The three modes of crack surface displacement
Diamagnetic Materials
Opaque
8. Undergo extensive plastic deformation prior to failure.
Color
Ductile Materials
Plastic Deformation (Metals)
Thermal expansion
9. 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.
Reflectance of Non-Metals
Extrinsic Semiconductors
Intergranular Fracture
Plastic Deformation (Metals)
10. Diffuse image
Ductile Materials
Lithography
Charpy or Izod test
Translucent
11. Different orientation of cleavage planes in grains.
Heat Capacity
Why fracture surfaces have faceted texture
Translucent
Extrinsic Semiconductors
12. They are used to assess properties of ceramics & glasses.
Bending tests
M is known as what?
Why fracture surfaces have faceted texture
What do magnetic moments arise from?
13. Wet: isotropic - under cut Dry: ansiotropic - directional
Etching
Bending tests
True Stress
Transparent
14. Increase temperature - increase in interatomic separation - thermal expansion
Elastic Deformation
Why materials fail in service
True Stress
Thermal Expansion: Asymmetric curve
15. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Force Decomposition
Soft Magnetic Materials
Coherent
Why fracture surfaces have faceted texture
16. Sigma=ln(li/lo)
True Strain
Why fracture surfaces have faceted texture
Insulators
Stress Intensity values
17. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Opacifiers
To improve fatigue life
Why materials fail in service
Engineering Fracture Performance
18. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
Why do ceramics have larger bonding energy?
Plastic Deformation (Metals)
Superconductivity
Bending tests
19. 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
Linewidth
Dependence of Heat Capacity on Temperature
4 Types of Magnetism
Not severe
20. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Etching
Pure Semiconductors: Conductivity vs. T
Extrinsic Semiconductors
Why fracture surfaces have faceted texture
21. 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
Thermal expansion
Liquid Crystal Displays (LCD's)
Thermal Conductivity
How an LCD works
22. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))
Work Hardening
Oxidation
True Stress
Opacifiers
23. Occur when lots of dislocations move.
Slip Bands
Iron-Silicon Alloy in Transformer Cores
Thermal Shock Resistance
Work Hardening
24. Metals are good conductors since their _______is only partially filled.
The three modes of crack surface displacement
Specific Heat
Valence band
Why fracture surfaces have faceted texture
25. 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
Domains in Ferromagnetic & Ferrimagnetic Materials
Thermal Expansion: Asymmetric curve
Liquid Crystal Displays (LCD's)
Reflection of Light for Metals
26. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Holloman Equation
Translucent
Incoherent
Iron-Silicon Alloy in Transformer Cores
27. Resistance to plastic deformation of cracking in compression - and better wear properties.
What do magnetic moments arise from?
Thermal expansion
Large Hardness
Fatigue
28. Cracks pass through grains - often along specific crystal planes.
Transgranular Fracture
Ductile Materials
Hardness
HB (Brinell Hardness)
29. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
HB (Brinell Hardness)
Thermal Expansion: Symmetric curve
Diamagnetic Materials
There is no perfect material?
30. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)
Two kinds of Reflection
Opaque
Coefficient of Thermal Expansion
Sparkle of Diamonds
31. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Impact energy
Energy States: Insulators and Semiconductors
Internal magnetic moments
Large Hardness
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.
Heat Capacity
Hardness
Meissner Effect
Opacity
33. 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
Slip Bands
Thermal Conductivity
Griffith Crack Model
Impact - Toughness
34. A measure of the ease with which a B field can be induced inside a material.
Scattering
Why fracture surfaces have faceted texture
Thermal Conductivity
Relative Permeability
35. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Pure Semiconductors: Conductivity vs. T
HB (Brinell Hardness)
Refraction
Intrinsic Semiconductors
36. Process by which metal atoms diffuse because of a potential.
There is no perfect material?
Holloman Equation
4 Types of Magnetism
Electromigration
37. 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.
Generation of a Magnetic Field - Within a Solid Material
Electromigration
Reflectance of Non-Metals
Thermal Conductivity
38. 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.
Oxidation
Iron-Silicon Alloy in Transformer Cores
True Strain
Scattering
39. 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.
Heat Capacity
Refraction
Coherent
Stress Intensity Factor
40. 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
Two ways to measure heat capacity
Paramagnetic Materials
Generation of a Magnetic Field - Within a Solid Material
Stress Intensity Factor
41. For a metal - there is no ______ - only reflection
Generation of a Magnetic Field - Vacuum
Refraction
Superconductivity
IC Devices: P-N Rectifying Junction
42. These materials are "attracted" to magnetic fields.
Iron-Silicon Alloy in Transformer Cores
Incoherent
Paramagnetic Materials
Meissner Effect
43. 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
Refraction
High impact energy
4 Types of Magnetism
44. 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."
Reflectance of Non-Metals
Insulators
Conduction & Electron Transport
Charpy or Izod test
45. Another optical property - Depends on the wavelength of the visible spectrum.
Intergranular Fracture
Thermal Expansion: Symmetric curve
Color
Magnetic Storage Media Types
46. The size of the material changes with a change in temperature - polymers have the largest values
Thermal expansion
Refraction
Coefficient of Thermal Expansion
Soft Magnetic Materials
47. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
Metallization
Thermal Stresses
Lithography
Engineering Fracture Performance
48. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Thermal expansion
Thermal Stresses
Ductile-to-Brittle Transition
Transgranular Fracture
49. 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)
Dependence of Heat Capacity on Temperature
Intergranular Fracture
Transparent
Rockwell
50. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.
Incoherent
Bending tests
Intergranular Fracture
Lithography