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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. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Thermal expansion
Work Hardening
Fourier's Law
Conduction & Electron Transport
2. 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
Film Deposition
Engineering Fracture Performance
How an LCD works
Specific Heat
3. Process by which metal atoms diffuse because of a potential.
Electromigration
Brittle Fracture
Stress Intensity values
Relative Permeability
4. Becomes harder (more strain) to stretch (elongate)
Thermal Shock Resistance
Work Hardening
To improve fatigue life
Film Deposition
5. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Why fracture surfaces have faceted texture
Slip Bands
Why do ceramics have larger bonding energy?
Why materials fail in service
6. 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
Superconductivity
Diamagnetic Materials
Why fracture surfaces have faceted texture
Stress Intensity Factor
7. Diffuse image
Pure Semiconductors: Conductivity vs. T
Rockwell
Translucent
Incoherent
8. 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.
Reflectance of Non-Metals
Modulus of Rupture (MOR)
IC Devices: P-N Rectifying Junction
Fourier's Law
9. For a metal - there is no ______ - only reflection
Refraction
M is known as what?
Thermal Shock Resistance
Slip Bands
10. Without passing a current a continually varying magnetic field will cause a current to flow
Work Hardening
Response to a Magnetic Field
Rockwell
Elastic Deformation
11. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Ductile Fracture
Fourier's Law
Where does DBTT occur?
Specific Heat
12. 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.
Refraction
Scattering
Translucent
Linewidth
13. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Work Hardening
Valence band
Oxidation
Hard Magnetic Materials
14. 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)
Energy States: Insulators and Semiconductors
Response to a Magnetic Field
Rockwell
Generation of a Magnetic Field - Vacuum
15. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
HB (Brinell Hardness)
What do magnetic moments arise from?
Film Deposition
There is no perfect material?
16. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Brittle Fracture
Fatigue
Why materials fail in service
Conduction & Electron Transport
17. Undergo extensive plastic deformation prior to failure.
Fourier's Law
Heat Capacity from an Atomic Prospective
Ductile Materials
Hard Magnetic Materials
18. 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.
To improve fatigue life
Linewidth
Insulators
Hard Magnetic Materials
19. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION
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20. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
IC Devices: P-N Rectifying Junction
Color
Ductile-to-Brittle Transition
Heat Capacity
21. 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.
Brittle Ceramics
Thermal expansion
Opacity
Large Hardness
22. ...occurs in bcc metals but not in fcc metals.
Where does DBTT occur?
Modulus of Rupture (MOR)
Iron-Silicon Alloy in Transformer Cores
Rockwell
23. Ability to transmit a clear image - The image is clear.
Transparent
Domains in Ferromagnetic & Ferrimagnetic Materials
Incoherent
Shear and Tensile Stress
24. 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
Ductile Materials
Yield and Reliability
Two kinds of Reflection
Coherent
25. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
True Stress
Linewidth
Energy States: Insulators and Semiconductors
Slip Bands
26. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.
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27. 1. Tensile (opening) 2. Sliding 3. Tearing
4 Types of Magnetism
Paramagnetic Materials
Two kinds of Reflection
The three modes of crack surface displacement
28. 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.
Transgranular Fracture
Plastic Deformation (Metals)
Stress Intensity Factor
Magnetic Storage
29. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
Superconductivity
Brittle Materials
Film Deposition
Hardness
30. 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
Brittle Ceramics
How an LCD works
Color
31. Width of smallest feature obtainable on Si surface
Not severe
Linewidth
Extrinsic Semiconductors
Charpy or Izod test
32. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Holloman Equation
Impact energy
Film Deposition
Two ways to measure heat capacity
33. A high index of refraction (n value) allows for multiple internal reactions.
Brittle Fracture
Sparkle of Diamonds
Shear and Tensile Stress
Thermal Shock Resistance
34. Undergo little or no plastic deformation.
Generation of a Magnetic Field - Vacuum
Brittle Materials
Insulators
Electromigration
35. Ohms Law: voltage drop = current * resistance
Influence of Temperature on Magnetic Behavior
Transparent
Ductile-to-Brittle Transition
Electrical Conduction
36. 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
Oxidation
Critical Properties of Superconductive Materials
Internal magnetic moments
Metals: Resistivity vs. T - Impurities
37. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))
Rockwell
The three modes of crack surface displacement
True Stress
Thermal Conductivity
38. 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
Relative Permeability
Translucent
Reflection of Light for Metals
Two ways to measure heat capacity
39. 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."
Incident Light
Charpy or Izod test
Hysteresis and Permanent Magnetization
Elastic Deformation
40. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Pure Semiconductors: Conductivity vs. T
Force Decomposition
Lithography
Intrinsic Semiconductors
41. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
Oxidation
What do magnetic moments arise from?
Impact energy
Electrical Conduction
42. The size of the material changes with a change in temperature - polymers have the largest values
Coefficient of Thermal Expansion
Fatigue
Oxidation
Thermal expansion
43. These materials are relatively unaffected by magnetic fields.
Diamagnetic Materials
4 Types of Magnetism
Impact - Toughness
Translucent
44. Is analogous to toughness.
Impact energy
Yield and Reliability
Coherent
Magnetic Storage Media Types
45. Light Amplification by Stimulated Emission of Radiation
Diamagnetic Materials
Luminescence examples
LASER
Impact - Toughness
46. 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
Iron-Silicon Alloy in Transformer Cores
Impact - Toughness
Soft Magnetic Materials
Ductile Materials
47. Occur when lots of dislocations move.
High impact energy
Insulators
Slip Bands
Large Hardness
48. 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
Two kinds of Reflection
Elastic Deformation
True Strain
How to gage the extent of plastic deformation
49. Second phase particles with n > glass.
Opacifiers
Slip Bands
Relative Permeability
How an LCD works
50. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
Oxidation
Impact energy
Brittle Fracture
Modulus of Rupture (MOR)