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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. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
Thermal Expansion: Asymmetric curve
Metallization
Brittle Fracture
Internal magnetic moments
2. Loss of image transmission - You get no image - There is no light transmission - and therefore reflects - scatters - or absorbs ALL of it. Both mirrors and carbon black are opaque.
Thermal Shock Resistance
Superconductivity
Opaque
Coefficient of Thermal Expansion
3. Typical loading conditions are _____ enough to break all inter-atomic bonds
Opaque
Thermal Stresses
Not severe
What do magnetic moments arise from?
4. These materials are relatively unaffected by magnetic fields.
Transgranular Fracture
Diamagnetic Materials
Paramagnetic Materials
IC Devices: P-N Rectifying Junction
5. 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
Diamagnetic Materials
Why materials fail in service
Linewidth
Critical Properties of Superconductive Materials
6. To build a device - various thin metal or insulating films are grown on top of each other - Evaporation - MBE - Sputtering - CVD (ALD)
Ductile-to-Brittle Transition
Impact - Toughness
Film Deposition
Rockwell
7. Undergo extensive plastic deformation prior to failure.
Heat Capacity from an Atomic Prospective
Superconductivity
Conduction & Electron Transport
Ductile Materials
8. 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
Two ways to measure heat capacity
Luminescence examples
Elastic Deformation
9. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
Meissner Effect
Transgranular Fracture
Influence of Temperature on Magnetic Behavior
IC Devices: P-N Rectifying Junction
10. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
Thermal Stresses
Thermal Conductivity
Slip Bands
True Strain
11. For a metal - there is no ______ - only reflection
Stages of Failure: Ductile Fracture
Two kinds of Reflection
Refraction
Electromigration
12. High toughness; material resists crack propagation.
Force Decomposition
High impact energy
HB (Brinell Hardness)
Opaque
13. A high index of refraction (n value) allows for multiple internal reactions.
Heat Capacity
Response to a Magnetic Field
Slip Bands
Sparkle of Diamonds
14. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
M is known as what?
Stages of Failure: Ductile Fracture
Force Decomposition
Pure Semiconductors: Conductivity vs. T
15. - 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
Thermal Shock Resistance
Charpy or Izod test
Modulus of Rupture (MOR)
Stress Intensity values
16. Elastic means reversible! This is not a permanent deformation.
Incoherent
Thermal expansion
Brittle Ceramics
Elastic Deformation
17. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)
Two kinds of Reflection
Griffith Crack Model
IC Devices: P-N Rectifying Junction
Critical Properties of Superconductive Materials
18. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Opacity
Generation of a Magnetic Field - Within a Solid Material
Thermal Conductivity
Why materials fail in service
19. 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.
Brittle Materials
Coefficient of Thermal Expansion
Large Hardness
Scattering
20. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Intrinsic Semiconductors
Holloman Equation
Large Hardness
Electrical Conduction
21. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
Stages of Failure: Ductile Fracture
What do magnetic moments arise from?
Incident Light
True Stress
22. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
Luminescence
Magnetic Storage Media Types
Modulus of Rupture (MOR)
Force Decomposition
23. Light Amplification by Stimulated Emission of Radiation
Electromigration
LASER
Impact energy
Incoherent
24. Different orientation of cleavage planes in grains.
Reflection of Light for Metals
Why fracture surfaces have faceted texture
Coefficient of Thermal Expansion
Heat Capacity
25. Ohms Law: voltage drop = current * resistance
Electrical Conduction
Slip Bands
Plastic Deformation (Metals)
Transgranular Fracture
26. Cracks propagate along grain boundaries.
Energy States: Insulators and Semiconductors
HB (Brinell Hardness)
Soft Magnetic Materials
Intergranular Fracture
27. 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
There is no perfect material?
Metallization
How an LCD works
Superconductivity
28. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION
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29. 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
Bending tests
Impact energy
Why materials fail in service
The Transistor
30. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
Conduction & Electron Transport
Coefficient of Thermal Expansion
Ductile Materials
Opacity
31. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Valence band
Metals: Resistivity vs. T - Impurities
Generation of a Magnetic Field - Vacuum
To improve fatigue life
32. Wet: isotropic - under cut Dry: ansiotropic - directional
Dependence of Heat Capacity on Temperature
Slip Bands
IC Devices: P-N Rectifying Junction
Etching
33. Cracks pass through grains - often along specific crystal planes.
Transgranular Fracture
Magnetic Storage
Shear and Tensile Stress
Critical Properties of Superconductive Materials
34. Emitted light is in phase
Coefficient of Thermal Expansion
Why materials fail in service
Coherent
Thermal Expansion: Asymmetric curve
35. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Transgranular Fracture
Generation of a Magnetic Field - Within a Solid Material
Paramagnetic Materials
Intrinsic Semiconductors
36. 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 Strain
Incoherent
How to gage the extent of plastic deformation
Hysteresis and Permanent Magnetization
37. If a material has ________ - then the field generated by those moments must be added to the induced field.
Two ways to measure heat capacity
Internal magnetic moments
Dependence of Heat Capacity on Temperature
Electromigration
38. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Refraction
Fatigue
Linewidth
Film Deposition
39. 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
High impact energy
Metals: Resistivity vs. T - Impurities
Why materials fail in service
Magnetic Storage
40. ...occurs in bcc metals but not in fcc metals.
Scattering
Yield and Reliability
Where does DBTT occur?
Rockwell
41. Diffuse image
Translucent
Thermal expansion
LASER
Hard Magnetic Materials
42. 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
Not severe
Color
Why do ceramics have larger bonding energy?
Oxidation
43. 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
Where does DBTT occur?
Color
Holloman Equation
Reflection of Light for Metals
44. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
Large Hardness
Engineering Fracture Performance
Hard Magnetic Materials
Dependence of Heat Capacity on Temperature
45. - 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
Internal magnetic moments
Luminescence
Reflectance of Non-Metals
Stages of Failure: Ductile Fracture
46. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Soft Magnetic Materials
Brittle Fracture
Metallization
There is no perfect material?
47. Sigma=ln(li/lo)
True Strain
Thermal Conductivity
Extrinsic Semiconductors
Force Decomposition
48. Metals are good conductors since their _______is only partially filled.
Conduction & Electron Transport
Valence band
Diamagnetic Materials
Internal magnetic moments
49. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Brittle Ceramics
Incident Light
Response to a Magnetic Field
Opaque
50. Hardness is the resistance of a material to deformation by indentation - Useful in quality control - Hardness can provide a qualitative assessment of strength - Hardness cannot be used to quantitatively infer strength or ductility.
Magnetic Storage Media Types
Hardness
Linewidth
Diamagnetic Materials