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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. The ability of a material to absorb heat - Quantitatively: The energy required to produce a unit rise in temperature for one mole of a material.
Thermal Stresses
Liquid Crystal Displays (LCD's)
Heat Capacity
To improve fatigue life
2. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Color
Thermal expansion
Magnetic Storage
Generation of a Magnetic Field - Within a Solid Material
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.
High impact energy
Reflectance of Non-Metals
Coherent
Thermal Stresses
4. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
Heat Capacity from an Atomic Prospective
Modulus of Rupture (MOR)
Energy States: Insulators and Semiconductors
Fourier's Law
5. 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
Thermal Stresses
Hysteresis and Permanent Magnetization
Ductile-to-Brittle Transition
6. There is always some statistical distribution of flaws or defects.
Diamagnetic Materials
There is no perfect material?
The three modes of crack surface displacement
Metallization
7. Cracks pass through grains - often along specific crystal planes.
Thermal Expansion: Asymmetric curve
Transgranular Fracture
4 Types of Magnetism
The three modes of crack surface displacement
8. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
Reflection of Light for Metals
Holloman Equation
Soft Magnetic Materials
Plastic Deformation (Metals)
9. 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
Coherent
Dependence of Heat Capacity on Temperature
Impact - Toughness
The Transistor
10. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION
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11. Because of ionic & covalent-type bonding.
Work Hardening
Modulus of Rupture (MOR)
Why do ceramics have larger bonding energy?
What do magnetic moments arise from?
12. 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
Stress Intensity Factor
Opaque
Charpy or Izod test
Energy States: Insulators and Semiconductors
13. 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
Fatigue
Iron-Silicon Alloy in Transformer Cores
Soft Magnetic Materials
Thermal Shock Resistance
14. Without passing a current a continually varying magnetic field will cause a current to flow
Response to a Magnetic Field
Brittle Fracture
Scattering
Transparent
15. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
Impact energy
Lithography
Coherent
What do magnetic moments arise from?
16. 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
Magnetic Storage
Translucent
Coherent
17. If a material has ________ - then the field generated by those moments must be added to the induced field.
Insulators
Modulus of Rupture (MOR)
Bending tests
Internal magnetic moments
18. Heat capacity.....- increases with temperature -for solids it reaches a limiting value of 3R
Thermal Expansion: Asymmetric curve
Generation of a Magnetic Field - Within a Solid Material
Ductile Fracture
Dependence of Heat Capacity on Temperature
19. 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
Reflection of Light for Metals
Magnetic Storage
M is known as what?
Thermal expansion
20. 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
Modulus of Rupture (MOR)
Thermal Shock Resistance
Intergranular Fracture
How to gage the extent of plastic deformation
21. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Brittle Ceramics
High impact energy
Force Decomposition
Superconductivity
22. Superconductors expel magnetic fields - This is why a superconductor will float above a magnet.
Fatigue
Meissner Effect
Heat Capacity
Brittle Materials
23. 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
Conduction & Electron Transport
Engineering Fracture Performance
The Transistor
4 Types of Magnetism
24. 1. Tensile (opening) 2. Sliding 3. Tearing
Two kinds of Reflection
Impact - Toughness
The three modes of crack surface displacement
Large Hardness
25. 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.
Plastic Deformation (Metals)
Griffith Crack Model
Opaque
Diamagnetic Materials
26. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Modulus of Rupture (MOR)
Ductile Fracture
Metallization
Plastic Deformation (Metals)
27. Ohms Law: voltage drop = current * resistance
What do magnetic moments arise from?
Brittle Ceramics
Electrical Conduction
Force Decomposition
28. Increase temperature - no increase in interatomic separation - no thermal expansion
High impact energy
Thermal Expansion: Symmetric curve
4 Types of Magnetism
Oxidation
29. Typical loading conditions are _____ enough to break all inter-atomic bonds
Not severe
Transparent
Extrinsic Semiconductors
The three modes of crack surface displacement
30. The size of the material changes with a change in temperature - polymers have the largest values
Generation of a Magnetic Field - Within a Solid Material
Thermal Conductivity
Coefficient of Thermal Expansion
Refraction
31. Metals are good conductors since their _______is only partially filled.
Valence band
Incident Light
Ductile Materials
Color
32. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Transparent
Energy States: Insulators and Semiconductors
Generation of a Magnetic Field - Within a Solid Material
Diamagnetic Materials
33. 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.
Electromigration
Brittle Ceramics
Not severe
Oxidation
34. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Stress Intensity values
Elastic Deformation
Generation of a Magnetic Field - Vacuum
Holloman Equation
35. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Extrinsic Semiconductors
How to gage the extent of plastic deformation
Charpy or Izod test
Refraction
36. 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
Intergranular Fracture
Elastic Deformation
How an LCD works
Stress Intensity Factor
37. 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 Stress
Not severe
Opaque
38. These materials are relatively unaffected by magnetic fields.
Diamagnetic Materials
Etching
Meissner Effect
Hardness
39. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.
Brittle Materials
Refraction
Large Hardness
Lithography
40. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Insulators
IC Devices: P-N Rectifying Junction
Domains in Ferromagnetic & Ferrimagnetic Materials
Etching
41. Emitted light is in phase
Coherent
Incident Light
Intrinsic Semiconductors
Large Hardness
42. 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.
Luminescence
Opaque
Not severe
Heat Capacity from an Atomic Prospective
43. Specific heat = energy input/(mass*temperature change)
Why do ceramics have larger bonding energy?
Oxidation
Specific Heat
Bending tests
44. 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.
Incident Light
Thermal Expansion: Asymmetric curve
Specific Heat
Scattering
45. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture
The three modes of crack surface displacement
Slip Bands
Stages of Failure: Ductile Fracture
Luminescence
46. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Ductile Materials
Hysteresis and Permanent Magnetization
Stress Intensity values
Why materials fail in service
47. ...occurs in bcc metals but not in fcc metals.
Incident Light
LASER
Large Hardness
Where does DBTT occur?
48. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
To improve fatigue life
Fatigue
Metals: Resistivity vs. T - Impurities
Opacity
49. 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
Luminescence examples
Two ways to measure heat capacity
Magnetic Storage
Brittle Ceramics
50. 1. Fluorescent Lamp - tungstate or silicate coating on inside of tube emits white light due to UV light generated inside the tube. 2. TV screen - emits light as electron beam is scanned back and forth.
Luminescence examples
Brittle Fracture
There is no perfect material?
Thermal Expansion: Asymmetric curve