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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. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Two kinds of Reflection
Paramagnetic Materials
Reflectance of Non-Metals
IC Devices: P-N Rectifying Junction
2. 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
IC Devices: P-N Rectifying Junction
To improve fatigue life
Diamagnetic Materials
3. 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
Scattering
4 Types of Magnetism
Brittle Ceramics
Translucent
4. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
True Strain
Why do ceramics have larger bonding energy?
4 Types of Magnetism
Generation of a Magnetic Field - Within a Solid Material
5. # of thermally generated electrons = # of holes (broken bonds)
Intrinsic Semiconductors
How to gage the extent of plastic deformation
Transparent
What do magnetic moments arise from?
6. Cracks propagate along grain boundaries.
Intergranular Fracture
How an LCD works
Influence of Temperature on Magnetic Behavior
Coefficient of Thermal Expansion
7. 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
Lithography
Not severe
Reflection of Light for Metals
8. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Large Hardness
Thermal Expansion: Asymmetric curve
Energy States: Insulators and Semiconductors
Force Decomposition
9. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Domains in Ferromagnetic & Ferrimagnetic Materials
Yield and Reliability
Generation of a Magnetic Field - Vacuum
Incident Light
10. 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 Expansion: Asymmetric curve
Oxidation
Diamagnetic Materials
Paramagnetic Materials
11. Typical loading conditions are _____ enough to break all inter-atomic bonds
True Stress
Reflection of Light for Metals
Electrical Conduction
Not severe
12. Because of ionic & covalent-type bonding.
Why do ceramics have larger bonding energy?
Iron-Silicon Alloy in Transformer Cores
Generation of a Magnetic Field - Vacuum
Liquid Crystal Displays (LCD's)
13. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Stress Intensity Factor
Metals: Resistivity vs. T - Impurities
Impact energy
Large Hardness
14. Sigma=ln(li/lo)
Ductile Materials
True Strain
Specific Heat
Intergranular Fracture
15. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Yield and Reliability
Large Hardness
Soft Magnetic Materials
Brittle Materials
16. The size of the material changes with a change in temperature - polymers have the largest values
High impact energy
Liquid Crystal Displays (LCD's)
Coefficient of Thermal Expansion
Why materials fail in service
17. Increase temperature - no increase in interatomic separation - no thermal expansion
Modulus of Rupture (MOR)
Scattering
Opacifiers
Thermal Expansion: Symmetric curve
18. Materials change size when temperature is changed
Heat Capacity from an Atomic Prospective
Thermal expansion
Coefficient of Thermal Expansion
Magnetic Storage
19. 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.
Thermal Conductivity
Brittle Ceramics
Incident Light
Force Decomposition
20. Second phase particles with n > glass.
Opacifiers
Meissner Effect
Stress Intensity Factor
Valence band
21. Wet: isotropic - under cut Dry: ansiotropic - directional
Luminescence examples
Fatigue
Thermal Expansion: Asymmetric curve
Etching
22. These materials are "attracted" to magnetic fields.
Paramagnetic Materials
Fatigue
Energy States: Insulators and Semiconductors
Fourier's Law
23. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R
Response to a Magnetic Field
Opacity
Dependence of Heat Capacity on Temperature
Intergranular Fracture
24. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Opaque
Intrinsic Semiconductors
Engineering Fracture Performance
Ductile-to-Brittle Transition
25. Stress concentration at a crack tips
Two kinds of Reflection
Griffith Crack Model
HB (Brinell Hardness)
Holloman Equation
26. Ability to transmit a clear image - The image is clear.
Ductile-to-Brittle Transition
Refraction
Liquid Crystal Displays (LCD's)
Transparent
27. 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
How an LCD works
Generation of a Magnetic Field - Within a Solid Material
Why materials fail in service
High impact energy
28. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
Ductile-to-Brittle Transition
4 Types of Magnetism
Internal magnetic moments
Superconductivity
29. 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
Extrinsic Semiconductors
Heat Capacity
Stress Intensity Factor
30. Undergo little or no plastic deformation.
Specific Heat
Sparkle of Diamonds
Brittle Materials
Valence band
31. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
Sparkle of Diamonds
Not severe
Rockwell
Influence of Temperature on Magnetic Behavior
32. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Generation of a Magnetic Field - Vacuum
Hard Magnetic Materials
High impact energy
Luminescence
33. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Electromigration
Slip Bands
Film Deposition
Pure Semiconductors: Conductivity vs. T
34. 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.
Relative Permeability
Scattering
Reflection of Light for Metals
M is known as what?
35. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.
Iron-Silicon Alloy in Transformer Cores
Insulators
Holloman Equation
Two ways to measure heat capacity
36. For a metal - there is no ______ - only reflection
Fourier's Law
Refraction
To improve fatigue life
Two ways to measure heat capacity
37. If a material has ________ - then the field generated by those moments must be added to the induced field.
Etching
Thermal Conductivity
Ductile-to-Brittle Transition
Internal magnetic moments
38. 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.
Sparkle of Diamonds
Reflectance of Non-Metals
Thermal Expansion: Asymmetric curve
Reflection of Light for Metals
39. 1. Tensile (opening) 2. Sliding 3. Tearing
Opacifiers
Slip Bands
Work Hardening
The three modes of crack surface displacement
40. Resistance to plastic deformation of cracking in compression - and better wear properties.
Color
Charpy or Izod test
Influence of Temperature on Magnetic Behavior
Large Hardness
41. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Opacity
Large Hardness
Force Decomposition
Linewidth
42. Metals are good conductors since their _______is only partially filled.
Fourier's Law
4 Types of Magnetism
Valence band
Thermal Conductivity
43. 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
Luminescence
True Strain
Specific Heat
44. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Generation of a Magnetic Field - Within a Solid Material
Slip Bands
Elastic Deformation
Engineering Fracture Performance
45. 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
Hardness
Griffith Crack Model
Response to a Magnetic Field
46. Light Amplification by Stimulated Emission of Radiation
Hysteresis and Permanent Magnetization
LASER
Transparent
Ductile-to-Brittle Transition
47. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.
Rockwell
Refraction
To improve fatigue life
Lithography
48. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)
Opaque
Charpy or Izod test
Incoherent
Magnetic Storage Media Types
49. They are used to assess properties of ceramics & glasses.
Bending tests
Why materials fail in service
Thermal Expansion: Symmetric curve
Thermal expansion
50. Occur when lots of dislocations move.
Slip Bands
Domains in Ferromagnetic & Ferrimagnetic Materials
Luminescence examples
Critical Properties of Superconductive Materials