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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. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Holloman Equation
Pure Semiconductors: Conductivity vs. T
Oxidation
Yield and Reliability
2. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.
To improve fatigue life
Slip Bands
Heat Capacity
Why fracture surfaces have faceted texture
3. 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 Fracture
Two kinds of Reflection
Opacifiers
4. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Opaque
Energy States: Insulators and Semiconductors
Hard Magnetic Materials
Stress Intensity values
5. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.
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6. Undergo extensive plastic deformation prior to failure.
Oxidation
Ductile Materials
Dependence of Heat Capacity on Temperature
Slip Bands
7. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Critical Properties of Superconductive Materials
Ductile-to-Brittle Transition
Meissner Effect
Transparent
8. The ability of a material to be rapidly cooled and not fracture
Brittle Fracture
Thermal Shock Resistance
The three modes of crack surface displacement
Electrical Conduction
9. For a metal - there is no ______ - only reflection
Sparkle of Diamonds
Refraction
Yield and Reliability
Liquid Crystal Displays (LCD's)
10. A measure of the ease with which a B field can be induced inside a material.
Generation of a Magnetic Field - Vacuum
Rockwell
Thermal expansion
Relative Permeability
11. Becomes harder (more strain) to stretch (elongate)
Generation of a Magnetic Field - Within a Solid Material
Specific Heat
Work Hardening
Conduction & Electron Transport
12. Occur when lots of dislocations move.
High impact energy
Energy States: Insulators and Semiconductors
Slip Bands
Electrical Conduction
13. 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)
Valence band
Lithography
Luminescence examples
Generation of a Magnetic Field - Vacuum
14. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Transgranular Fracture
Coherent
Dependence of Heat Capacity on Temperature
Conduction & Electron Transport
15. 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
Response to a Magnetic Field
M is known as what?
Generation of a Magnetic Field - Within a Solid Material
Refraction
16. ...occurs in bcc metals but not in fcc metals.
Where does DBTT occur?
What do magnetic moments arise from?
Opacity
Conduction & Electron Transport
17. Elastic means reversible! This is not a permanent deformation.
Film Deposition
Fourier's Law
Elastic Deformation
How an LCD works
18. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Coherent
Pure Semiconductors: Conductivity vs. T
Soft Magnetic Materials
Influence of Temperature on Magnetic Behavior
19. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Extrinsic Semiconductors
Not severe
Stress Intensity values
Oxidation
20. Process by which metal atoms diffuse because of a potential.
Shear and Tensile Stress
Electromigration
Refraction
Why materials fail in service
21. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Engineering Fracture Performance
Large Hardness
Oxidation
Generation of a Magnetic Field - Vacuum
22. Different orientation of cleavage planes in grains.
Why fracture surfaces have faceted texture
Insulators
Rockwell
Heat Capacity
23. 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."
Response to a Magnetic Field
Charpy or Izod test
Impact - Toughness
Internal magnetic moments
24. Emitted light is in phase
Dependence of Heat Capacity on Temperature
Coherent
Paramagnetic Materials
Charpy or Izod test
25. Cracks pass through grains - often along specific crystal planes.
Magnetic Storage
Transgranular Fracture
The three modes of crack surface displacement
Ductile Materials
26. Increase temperature - no increase in interatomic separation - no thermal expansion
Translucent
Work Hardening
Thermal Expansion: Symmetric curve
Elastic Deformation
27. Cracks propagate along grain boundaries.
Where does DBTT occur?
Plastic Deformation (Metals)
Intergranular Fracture
Incident Light
28. Specific heat = energy input/(mass*temperature change)
Response to a Magnetic Field
Electrical Conduction
Why do ceramics have larger bonding energy?
Specific Heat
29. 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.
Scattering
Iron-Silicon Alloy in Transformer Cores
Engineering Fracture Performance
Opacifiers
30. - The emission of light from a substance due to the absorption of energy. (Could be radiation - mechanical - or chemical energy. Could also be energetic particles.) - Traps and activator levels are produced by impurity additions to the material - Whe
Plastic Deformation (Metals)
Critical Properties of Superconductive Materials
How to gage the extent of plastic deformation
Luminescence
31. 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
Oxidation
The Transistor
Stress Intensity values
Opaque
32. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
Liquid Crystal Displays (LCD's)
Bending tests
Thermal Stresses
M is known as what?
33. These materials are "attracted" to magnetic fields.
Slip Bands
Large Hardness
Diamagnetic Materials
Paramagnetic Materials
34. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Pure Semiconductors: Conductivity vs. T
Conduction & Electron Transport
Incoherent
Scattering
35. There is always some statistical distribution of flaws or defects.
Refraction
4 Types of Magnetism
Opacity
There is no perfect material?
36. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.
Rockwell
Ductile-to-Brittle Transition
Heat Capacity from an Atomic Prospective
Large Hardness
37. They are used to assess properties of ceramics & glasses.
Electromigration
Bending tests
HB (Brinell Hardness)
Where does DBTT occur?
38. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Two kinds of Reflection
Luminescence examples
Not severe
Incident Light
39. If a material has ________ - then the field generated by those moments must be added to the induced field.
Internal magnetic moments
There is no perfect material?
Energy States: Insulators and Semiconductors
Incoherent
40. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
Rockwell
Thermal expansion
Intergranular Fracture
HB (Brinell Hardness)
41. Width of smallest feature obtainable on Si surface
Paramagnetic Materials
Oxidation
Conduction & Electron Transport
Linewidth
42. These materials are relatively unaffected by magnetic fields.
Shear and Tensile Stress
Valence band
Ductile Fracture
Diamagnetic Materials
43. 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
Oxidation
Meissner Effect
Influence of Temperature on Magnetic Behavior
4 Types of Magnetism
44. Materials change size when temperature is changed
Thermal expansion
Response to a Magnetic Field
Electromigration
Reflectance of Non-Metals
45. 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
Holloman Equation
Large Hardness
Internal magnetic moments
46. The size of the material changes with a change in temperature - polymers have the largest values
Refraction
IC Devices: P-N Rectifying Junction
Coefficient of Thermal Expansion
Intergranular Fracture
47. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.
Magnetic Storage Media Types
Electromigration
Refraction
Meissner Effect
48. Undergo little or no plastic deformation.
Fatigue
Thermal Stresses
Brittle Materials
Color
49. Diffuse image
Translucent
Electromigration
Work Hardening
How an LCD works
50. 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.
Ductile Fracture
Influence of Temperature on Magnetic Behavior
M is known as what?
Heat Capacity