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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. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Shear and Tensile Stress
Thermal Expansion: Symmetric curve
Energy States: Insulators and Semiconductors
Brittle Fracture
2. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
Influence of Temperature on Magnetic Behavior
Response to a Magnetic Field
Specific Heat
Opacifiers
3. Diffuse image
Translucent
Stages of Failure: Ductile Fracture
Opacifiers
Soft Magnetic Materials
4. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Reflection of Light for Metals
Hard Magnetic Materials
Incoherent
Transgranular Fracture
5. The ability of a material to be rapidly cooled and not fracture
Why materials fail in service
Brittle Materials
Thermal Shock Resistance
To improve fatigue life
6. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
HB (Brinell Hardness)
Reflectance of Non-Metals
Valence band
Fourier's Law
7. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Work Hardening
4 Types of Magnetism
Elastic Deformation
Force Decomposition
8. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Large Hardness
Incoherent
Reflection of Light for Metals
Generation of a Magnetic Field - Vacuum
9. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Incident Light
Ductile-to-Brittle Transition
Charpy or Izod test
Generation of a Magnetic Field - Vacuum
10. Second phase particles with n > glass.
Opacifiers
Impact - Toughness
To improve fatigue life
True Strain
11. Ability to transmit a clear image - The image is clear.
Transparent
Conduction & Electron Transport
Paramagnetic Materials
HB (Brinell Hardness)
12. Light Amplification by Stimulated Emission of Radiation
Transparent
M is known as what?
Meissner Effect
LASER
13. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Incident Light
Plastic Deformation (Metals)
Meissner Effect
Specific Heat
14. 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
Paramagnetic Materials
Thermal Shock Resistance
Metallization
15. - 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
Soft Magnetic Materials
Internal magnetic moments
Dependence of Heat Capacity on Temperature
Luminescence
16. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
Two kinds of Reflection
Force Decomposition
Modulus of Rupture (MOR)
Fatigue
17. 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.
Transgranular Fracture
What do magnetic moments arise from?
Scattering
Metallization
18. Width of smallest feature obtainable on Si surface
4 Types of Magnetism
To improve fatigue life
Linewidth
Fatigue
19. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION
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20. 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
True Strain
Elastic Deformation
Brittle Materials
21. High toughness; material resists crack propagation.
Insulators
Sparkle of Diamonds
High impact energy
Opacifiers
22. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)
Film Deposition
Two kinds of Reflection
Impact - Toughness
What do magnetic moments arise from?
23. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Brittle Materials
Fatigue
Luminescence
Thermal Stresses
24. 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
Color
Stress Intensity Factor
Internal magnetic moments
Heat Capacity
25. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.
How an LCD works
Metallization
What do magnetic moments arise from?
Transparent
26. Because of ionic & covalent-type bonding.
Metals: Resistivity vs. T - Impurities
Why do ceramics have larger bonding energy?
Heat Capacity from an Atomic Prospective
Paramagnetic Materials
27. Metals are good conductors since their _______is only partially filled.
Paramagnetic Materials
Etching
Domains in Ferromagnetic & Ferrimagnetic Materials
Valence band
28. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
HB (Brinell Hardness)
Ductile Fracture
Engineering Fracture Performance
Magnetic Storage Media Types
29. 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)
Response to a Magnetic Field
Thermal Expansion: Asymmetric curve
Generation of a Magnetic Field - Vacuum
Why fracture surfaces have faceted texture
30. 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
Dependence of Heat Capacity on Temperature
4 Types of Magnetism
Stress Intensity values
Hardness
31. Is analogous to toughness.
Yield and Reliability
Film Deposition
Generation of a Magnetic Field - Vacuum
Impact energy
32. 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
Engineering Fracture Performance
Specific Heat
Magnetic Storage
Diamagnetic Materials
33. Stress concentration at a crack tips
Electrical Conduction
Griffith Crack Model
Energy States: Insulators and Semiconductors
Intrinsic Semiconductors
34. Resistance to plastic deformation of cracking in compression - and better wear properties.
Large Hardness
Lithography
Thermal Expansion: Symmetric curve
Iron-Silicon Alloy in Transformer Cores
35. 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
Scattering
Oxidation
Energy States: Insulators and Semiconductors
Generation of a Magnetic Field - Vacuum
36. Cracks propagate along grain boundaries.
Impact - Toughness
Conduction & Electron Transport
How to gage the extent of plastic deformation
Intergranular Fracture
37. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
Refraction
True Stress
Superconductivity
Why fracture surfaces have faceted texture
38. Sigma=ln(li/lo)
Reflection of Light for Metals
Pure Semiconductors: Conductivity vs. T
Opacifiers
True Strain
39. The magnetic hysteresis phenomenon: Stage 1: Initial (unmagnetized state) Stage 2: Apply H - align domains Stage 3: Remove H - alignment remains => Permanent magnet Stage 4: Coercivity - Hc negative H needed to demagnitize Stage 5: Apply -H - align d
True Stress
Two ways to measure heat capacity
Hysteresis and Permanent Magnetization
Why materials fail in service
40. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Soft Magnetic Materials
Thermal Expansion: Symmetric curve
Not severe
Hysteresis and Permanent Magnetization
41. 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.
Dependence of Heat Capacity on Temperature
Superconductivity
Generation of a Magnetic Field - Within a Solid Material
Insulators
42. Cracks pass through grains - often along specific crystal planes.
Linewidth
Translucent
Transgranular Fracture
Two ways to measure heat capacity
43. Without passing a current a continually varying magnetic field will cause a current to flow
Refraction
Response to a Magnetic Field
Luminescence
What do magnetic moments arise from?
44. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
IC Devices: P-N Rectifying Junction
Intergranular Fracture
Generation of a Magnetic Field - Within a Solid Material
The Transistor
45. 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
Magnetic Storage
Refraction
Transgranular Fracture
Yield and Reliability
46. - 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
Response to a Magnetic Field
Generation of a Magnetic Field - Within a Solid Material
Not severe
Stress Intensity values
47. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
Thermal Stresses
Large Hardness
Brittle Fracture
Electromigration
48. 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
Extrinsic Semiconductors
Iron-Silicon Alloy in Transformer Cores
To improve fatigue life
Ductile Materials
49. Different orientation of cleavage planes in grains.
Color
Oxidation
Why fracture surfaces have faceted texture
Shear and Tensile Stress
50. They are used to assess properties of ceramics & glasses.
Bending tests
True Stress
Charpy or Izod test
Color