SUBJECTS
|
BROWSE
|
CAREER CENTER
|
POPULAR
|
JOIN
|
LOGIN
Business Skills
|
Soft Skills
|
Basic Literacy
|
Certifications
About
|
Help
|
Privacy
|
Terms
|
Email
Search
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. Rho=F/A - tau=G/A . Depending on what angle the force is applied - and what angle the crystal is at - it takes different amounts of force to induce plastic deformation.
Shear and Tensile Stress
Brittle Materials
Metallization
True Stress
2. These materials are "attracted" to magnetic fields.
Magnetic Storage Media Types
Where does DBTT occur?
Paramagnetic Materials
How to gage the extent of plastic deformation
3. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Intrinsic Semiconductors
HB (Brinell Hardness)
Holloman Equation
Incident Light
4. 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
Paramagnetic Materials
Why fracture surfaces have faceted texture
Reflection of Light for Metals
Bending tests
5. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Electromigration
Ductile-to-Brittle Transition
Scattering
Diamagnetic Materials
6. The ability of a material to be rapidly cooled and not fracture
Fatigue
Intrinsic Semiconductors
How an LCD works
Thermal Shock Resistance
7. 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
Stages of Failure: Ductile Fracture
Refraction
Insulators
Brittle Fracture
8. Increase temperature - increase in interatomic separation - thermal expansion
Brittle Fracture
Critical Properties of Superconductive Materials
True Strain
Thermal Expansion: Asymmetric curve
9. 1. Tensile (opening) 2. Sliding 3. Tearing
Paramagnetic Materials
Shear and Tensile Stress
Stages of Failure: Ductile Fracture
The three modes of crack surface displacement
10. Without passing a current a continually varying magnetic field will cause a current to flow
Specific Heat
Response to a Magnetic Field
Stress Intensity Factor
Color
11. 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
Where does DBTT occur?
Extrinsic Semiconductors
Energy States: Insulators and Semiconductors
12. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R
Dependence of Heat Capacity on Temperature
Scattering
Influence of Temperature on Magnetic Behavior
Superconductivity
13. Metals are good conductors since their _______is only partially filled.
Valence band
Thermal Expansion: Asymmetric curve
Hysteresis and Permanent Magnetization
Sparkle of Diamonds
14. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
M is known as what?
IC Devices: P-N Rectifying Junction
Force Decomposition
Electrical Conduction
15. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
Thermal Stresses
Metals: Resistivity vs. T - Impurities
LASER
Reflectance of Non-Metals
16. Elastic means reversible! This is not a permanent deformation.
Hard Magnetic Materials
Why do ceramics have larger bonding energy?
Elastic Deformation
Dependence of Heat Capacity on Temperature
17. 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."
Fatigue
Charpy or Izod test
Oxidation
Heat Capacity from an Atomic Prospective
18. Emitted light is in phase
Coherent
Thermal Conductivity
Griffith Crack Model
Where does DBTT occur?
19. 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)
Brittle Fracture
Meissner Effect
Charpy or Izod test
Rockwell
20. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Intrinsic Semiconductors
Superconductivity
Why materials fail in service
Reflectance of Non-Metals
21. Ability to transmit a clear image - The image is clear.
M is known as what?
Transparent
IC Devices: P-N Rectifying Junction
Brittle Fracture
22. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Soft Magnetic Materials
Valence band
Opacifiers
Thermal Expansion: Symmetric curve
23. These materials are relatively unaffected by magnetic fields.
Meissner Effect
Energy States: Insulators and Semiconductors
Opacifiers
Diamagnetic Materials
24. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
True Stress
IC Devices: P-N Rectifying Junction
Domains in Ferromagnetic & Ferrimagnetic Materials
HB (Brinell Hardness)
25. 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
Oxidation
True Strain
Soft Magnetic Materials
Generation of a Magnetic Field - Within a Solid Material
26. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Conduction & Electron Transport
True Stress
IC Devices: P-N Rectifying Junction
Impact - Toughness
27. Cracks pass through grains - often along specific crystal planes.
Diamagnetic Materials
Refraction
Transgranular Fracture
Engineering Fracture Performance
28. Diffuse image
Translucent
Coherent
Domains in Ferromagnetic & Ferrimagnetic Materials
Modulus of Rupture (MOR)
29. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Color
Meissner Effect
Intergranular Fracture
Extrinsic Semiconductors
30. 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
Intergranular Fracture
Two kinds of Reflection
Linewidth
31. - Metals that exhibit high ductility - exhibit high toughness. Ceramics are very strong - but have low ductility and low toughness - Polymers are very ductile but are not generally very strong in shear (compared to metals and ceramics). They have low
Intergranular Fracture
Response to a Magnetic Field
Stress Intensity values
Magnetic Storage
32. A measure of the ease with which a B field can be induced inside a material.
Brittle Ceramics
4 Types of Magnetism
Opaque
Relative Permeability
33. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Fatigue
Stages of Failure: Ductile Fracture
Force Decomposition
Heat Capacity
34. 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.
Generation of a Magnetic Field - Within a Solid Material
Two ways to measure heat capacity
Brittle Ceramics
Pure Semiconductors: Conductivity vs. T
35. Increase temperature - no increase in interatomic separation - no thermal expansion
Shear and Tensile Stress
Reflection of Light for Metals
Thermal Expansion: Symmetric curve
Slip Bands
36. Materials change size when temperature is changed
Coefficient of Thermal Expansion
Coherent
Thermal expansion
Fatigue
37. Because of ionic & covalent-type bonding.
Why materials fail in service
Domains in Ferromagnetic & Ferrimagnetic Materials
Why do ceramics have larger bonding energy?
Relative Permeability
38. 1. Ability of the material to absorb energy prior to fracture 2. Short term dynamic stressing - Car collisions - Bullets - Athletic equipment 3. This is different than toughness; energy necessary to push a crack (flaw) through a material 4. Useful in
Impact - Toughness
Intergranular Fracture
Ductile Materials
Incident Light
39. 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
Translucent
IC Devices: P-N Rectifying Junction
Metals: Resistivity vs. T - Impurities
40. They are used to assess properties of ceramics & glasses.
Sparkle of Diamonds
Bending tests
Stress Intensity Factor
The Transistor
41. 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
The Transistor
Scattering
Electrical Conduction
42. 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
Griffith Crack Model
Valence band
Luminescence
The Transistor
43. - 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
Electrical Conduction
Luminescence
HB (Brinell Hardness)
Where does DBTT occur?
44. Sigma=ln(li/lo)
True Strain
Domains in Ferromagnetic & Ferrimagnetic Materials
Ductile-to-Brittle Transition
Reflection of Light for Metals
45. 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
4 Types of Magnetism
Slip Bands
Yield and Reliability
Coherent
46. 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
Response to a Magnetic Field
Intrinsic Semiconductors
Stages of Failure: Ductile Fracture
47. 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.
Soft Magnetic Materials
Reflectance of Non-Metals
Why do ceramics have larger bonding energy?
Pure Semiconductors: Conductivity vs. T
48. 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.
Engineering Fracture Performance
Coefficient of Thermal Expansion
Metals: Resistivity vs. T - Impurities
Insulators
49. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)
Plastic Deformation (Metals)
Pure Semiconductors: Conductivity vs. T
Film Deposition
Shear and Tensile Stress
50. The size of the material changes with a change in temperature - polymers have the largest values
Soft Magnetic Materials
Transgranular Fracture
Refraction
Coefficient of Thermal Expansion