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. The size of the material changes with a change in temperature - polymers have the largest values
Coefficient of Thermal Expansion
Holloman Equation
Brittle Materials
What do magnetic moments arise from?
2. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Holloman Equation
Coherent
Luminescence
IC Devices: P-N Rectifying Junction
3. 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
Critical Properties of Superconductive Materials
Coherent
Linewidth
4. Light Amplification by Stimulated Emission of Radiation
Intrinsic Semiconductors
LASER
Reflection of Light for Metals
Relative Permeability
5. ...occurs in bcc metals but not in fcc metals.
Scattering
Where does DBTT occur?
Iron-Silicon Alloy in Transformer Cores
Two ways to measure heat capacity
6. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
Diamagnetic Materials
Thermal Expansion: Asymmetric curve
Brittle Fracture
Thermal Stresses
7. 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.
Reflectance of Non-Metals
Hardness
Opaque
Shear and Tensile Stress
8. 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
Etching
Rockwell
4 Types of Magnetism
Thermal expansion
9. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)
Film Deposition
Engineering Fracture Performance
Griffith Crack Model
Ductile-to-Brittle Transition
10. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Iron-Silicon Alloy in Transformer Cores
Domains in Ferromagnetic & Ferrimagnetic Materials
Opaque
Ductile Fracture
11. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
Heat Capacity from an Atomic Prospective
Linewidth
Coherent
Thermal Stresses
12. Second phase particles with n > glass.
Charpy or Izod test
Brittle Fracture
Opacifiers
Etching
13. These materials are relatively unaffected by magnetic fields.
Diamagnetic Materials
Magnetic Storage
Brittle Fracture
Paramagnetic Materials
14. 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
Yield and Reliability
M is known as what?
What do magnetic moments arise from?
Superconductivity
15. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
IC Devices: P-N Rectifying Junction
To improve fatigue life
Elastic Deformation
Heat Capacity
16. Typical loading conditions are _____ enough to break all inter-atomic bonds
Not severe
Large Hardness
How an LCD works
Intrinsic Semiconductors
17. 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
Generation of a Magnetic Field - Vacuum
Specific Heat
How an LCD works
Coefficient of Thermal Expansion
18. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Incoherent
Critical Properties of Superconductive Materials
Ductile Materials
Coherent
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.
Brittle Ceramics
IC Devices: P-N Rectifying Junction
Brittle Fracture
Fourier's Law
20. 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
Hardness
Paramagnetic Materials
Refraction
Yield and Reliability
21. 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
Pure Semiconductors: Conductivity vs. T
Valence band
Brittle Ceramics
22. 1. Hard disk drives (granular/perpendicular media) 2. Recording tape (particulate media)
Work Hardening
Bending tests
Magnetic Storage Media Types
Stages of Failure: Ductile Fracture
23. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
To improve fatigue life
Thermal expansion
Yield and Reliability
Why materials fail in service
24. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Opaque
Color
Ductile-to-Brittle Transition
Griffith Crack Model
25. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Heat Capacity from an Atomic Prospective
Stress Intensity Factor
Extrinsic Semiconductors
IC Devices: P-N Rectifying Junction
26. 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
Dependence of Heat Capacity on Temperature
Film Deposition
Engineering Fracture Performance
27. Ability to transmit a clear image - The image is clear.
Transparent
Translucent
Generation of a Magnetic Field - Within a Solid Material
Refraction
28. Diffuse image
IC Devices: P-N Rectifying Junction
Large Hardness
Shear and Tensile Stress
Translucent
29. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Magnetic Storage Media Types
Energy States: Insulators and Semiconductors
Not severe
Fatigue
30. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
Paramagnetic Materials
Influence of Temperature on Magnetic Behavior
Impact - Toughness
How an LCD works
31. The Magnetization of the material - and is essentially the dipole moment per unit volume. It is proportional to the applied field. Xm is the magnetic susceptibility.
How to gage the extent of plastic deformation
Thermal expansion
Scattering
M is known as what?
32. Ohms Law: voltage drop = current * resistance
Impact energy
Electrical Conduction
Magnetic Storage Media Types
Why materials fail in service
33. 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
Plastic Deformation (Metals)
Why do ceramics have larger bonding energy?
Oxidation
Hard Magnetic Materials
34. Cracks propagate along grain boundaries.
There is no perfect material?
Relative Permeability
Intergranular Fracture
Refraction
35. 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
Stages of Failure: Ductile Fracture
Reflection of Light for Metals
Paramagnetic Materials
To improve fatigue life
36. For a metal - there is no ______ - only reflection
Slip Bands
Work Hardening
Refraction
Conduction & Electron Transport
37. # of thermally generated electrons = # of holes (broken bonds)
Luminescence examples
Sparkle of Diamonds
Intrinsic Semiconductors
Extrinsic Semiconductors
38. Different orientation of cleavage planes in grains.
Domains in Ferromagnetic & Ferrimagnetic Materials
Opacifiers
Diamagnetic Materials
Why fracture surfaces have faceted texture
39. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
To improve fatigue life
Modulus of Rupture (MOR)
Refraction
What do magnetic moments arise from?
40. High toughness; material resists crack propagation.
There is no perfect material?
Ductile Materials
Incident Light
High impact energy
41. 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.
Paramagnetic Materials
Opacity
Hysteresis and Permanent Magnetization
Brittle Materials
42. Because of ionic & covalent-type bonding.
Soft Magnetic Materials
Why do ceramics have larger bonding energy?
Elastic Deformation
Holloman Equation
43. 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)
Relative Permeability
Two kinds of Reflection
4 Types of Magnetism
Generation of a Magnetic Field - Vacuum
44. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Metals: Resistivity vs. T - Impurities
Yield and Reliability
Specific Heat
Conduction & Electron Transport
45. - 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
IC Devices: P-N Rectifying Junction
Coherent
Stress Intensity values
Engineering Fracture Performance
46. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Modulus of Rupture (MOR)
Thermal expansion
Reflection of Light for Metals
Engineering Fracture Performance
47. Process by which metal atoms diffuse because of a potential.
Incoherent
Electromigration
Brittle Materials
Translucent
48. Becomes harder (more strain) to stretch (elongate)
Iron-Silicon Alloy in Transformer Cores
Work Hardening
Luminescence examples
Etching
49. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Linewidth
Opacifiers
Fatigue
Luminescence examples
50. 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."
Metals: Resistivity vs. T - Impurities
Thermal Expansion: Asymmetric curve
Charpy or Izod test
Yield and Reliability