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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. 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
Bending tests
Ductile Materials
Transparent
Oxidation
2. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Engineering Fracture Performance
Refraction
Stress Intensity values
Work Hardening
3. - 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
Energy States: Insulators and Semiconductors
Luminescence
Relative Permeability
Meissner Effect
4. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Incident Light
Domains in Ferromagnetic & Ferrimagnetic Materials
True Stress
HB (Brinell Hardness)
5. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture
Work Hardening
Stages of Failure: Ductile Fracture
Lithography
Opacity
6. 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
LASER
Magnetic Storage
Generation of a Magnetic Field - Within a Solid Material
Brittle Ceramics
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.
Pure Semiconductors: Conductivity vs. T
Shear and Tensile Stress
Energy States: Insulators and Semiconductors
Internal magnetic moments
8. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Shear and Tensile Stress
Conduction & Electron Transport
Thermal Conductivity
Hard Magnetic Materials
9. 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.
Diamagnetic Materials
Reflection of Light for Metals
Specific Heat
M is known as what?
10. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Electrical Conduction
True Stress
Force Decomposition
Coherent
11. 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
Insulators
Impact energy
Reflection of Light for Metals
Paramagnetic Materials
12. Becomes harder (more strain) to stretch (elongate)
To improve fatigue life
Work Hardening
There is no perfect material?
Meissner Effect
13. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
The three modes of crack surface displacement
Pure Semiconductors: Conductivity vs. T
Holloman Equation
Modulus of Rupture (MOR)
14. # of thermally generated electrons = # of holes (broken bonds)
Bending tests
Color
Intrinsic Semiconductors
Refraction
15. 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.
Transparent
Relative Permeability
Generation of a Magnetic Field - Vacuum
Insulators
16. - 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
Opaque
Soft Magnetic Materials
Stress Intensity values
Why fracture surfaces have faceted texture
17. Elastic means reversible! This is not a permanent deformation.
Superconductivity
Elastic Deformation
Incoherent
Yield and Reliability
18. If a material has ________ - then the field generated by those moments must be added to the induced field.
Paramagnetic Materials
Reflectance of Non-Metals
Internal magnetic moments
Meissner Effect
19. 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
Critical Properties of Superconductive Materials
HB (Brinell Hardness)
Slip Bands
Why fracture surfaces have faceted texture
20. Process by which metal atoms diffuse because of a potential.
Electromigration
Force Decomposition
Hard Magnetic Materials
Soft Magnetic Materials
21. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R
Slip Bands
Dependence of Heat Capacity on Temperature
Holloman Equation
Reflection of Light for Metals
22. 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
Where does DBTT occur?
Luminescence
Oxidation
23. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Color
Slip Bands
Extrinsic Semiconductors
Critical Properties of Superconductive Materials
24. Another optical property - Depends on the wavelength of the visible spectrum.
Reflectance of Non-Metals
Color
M is known as what?
Shear and Tensile Stress
25. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Valence band
Why materials fail in service
Oxidation
Reflectance of Non-Metals
26. Materials change size when temperature is changed
Translucent
Thermal expansion
Bending tests
Reflectance of Non-Metals
27. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
Stress Intensity Factor
Brittle Fracture
Meissner Effect
Stages of Failure: Ductile Fracture
28. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Hardness
Force Decomposition
Holloman Equation
Response to a Magnetic Field
29. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
Influence of Temperature on Magnetic Behavior
Modulus of Rupture (MOR)
Etching
Critical Properties of Superconductive Materials
30. 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.
Heat Capacity from an Atomic Prospective
Scattering
Oxidation
Refraction
31. Light Amplification by Stimulated Emission of Radiation
LASER
Dependence of Heat Capacity on Temperature
Sparkle of Diamonds
Oxidation
32. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Opacifiers
To improve fatigue life
Reflection of Light for Metals
Conduction & Electron Transport
33. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Lithography
Griffith Crack Model
Ductile Fracture
Domains in Ferromagnetic & Ferrimagnetic Materials
34. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
Heat Capacity from an Atomic Prospective
HB (Brinell Hardness)
Brittle Materials
Iron-Silicon Alloy in Transformer Cores
35. There is always some statistical distribution of flaws or defects.
Influence of Temperature on Magnetic Behavior
Thermal Stresses
There is no perfect material?
Insulators
36. Stress concentration at a crack tips
Griffith Crack Model
Impact - Toughness
Two ways to measure heat capacity
Reflectance of Non-Metals
37. Cracks pass through grains - often along specific crystal planes.
Scattering
Insulators
Transgranular Fracture
Intrinsic Semiconductors
38. Increase temperature - increase in interatomic separation - thermal expansion
How to gage the extent of plastic deformation
Thermal Expansion: Asymmetric curve
Charpy or Izod test
Rockwell
39. 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
Reflectance of Non-Metals
Brittle Materials
Fourier's Law
The Transistor
40. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Metals: Resistivity vs. T - Impurities
Engineering Fracture Performance
Force Decomposition
Rockwell
41. 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.
Opacity
Luminescence examples
Metals: Resistivity vs. T - Impurities
Plastic Deformation (Metals)
42. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Energy States: Insulators and Semiconductors
Lithography
Slip Bands
Ductile-to-Brittle Transition
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
4 Types of Magnetism
Magnetic Storage
Internal magnetic moments
Stages of Failure: Ductile Fracture
44. Resistance to plastic deformation of cracking in compression - and better wear properties.
Oxidation
Thermal expansion
Why do ceramics have larger bonding energy?
Large Hardness
45. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)
Fatigue
Scattering
What do magnetic moments arise from?
Two kinds of Reflection
46. 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
Meissner Effect
Reflectance of Non-Metals
HB (Brinell Hardness)
47. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Two kinds of Reflection
Pure Semiconductors: Conductivity vs. T
Scattering
Thermal Expansion: Symmetric curve
48. Occur when lots of dislocations move.
Slip Bands
Impact energy
Insulators
Thermal Stresses
49. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Generation of a Magnetic Field - Within a Solid Material
Ductile Fracture
Fatigue
Brittle Ceramics
50. 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
Thermal Expansion: Symmetric curve
Hard Magnetic Materials
Why fracture surfaces have faceted texture
Hysteresis and Permanent Magnetization