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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. 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
Griffith Crack Model
Iron-Silicon Alloy in Transformer Cores
Thermal Expansion: Symmetric curve
Luminescence
2. Is analogous to toughness.
Reflection of Light for Metals
Impact energy
Paramagnetic Materials
Luminescence
3. Increase temperature - no increase in interatomic separation - no thermal expansion
Thermal Expansion: Symmetric curve
Stages of Failure: Ductile Fracture
Lithography
Transgranular Fracture
4. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
Superconductivity
Engineering Fracture Performance
Transgranular Fracture
Bending tests
5. heat flux = -(thermal conductivity)(temperature gradient) - Defines heat transfer by CONDUCTION
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6. 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.
Work Hardening
Impact - Toughness
Sparkle of Diamonds
Scattering
7. 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)
Generation of a Magnetic Field - Vacuum
Hard Magnetic Materials
Lithography
Diamagnetic Materials
8. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))
Energy States: Insulators and Semiconductors
Why materials fail in service
Dependence of Heat Capacity on Temperature
True Stress
9. Because of ionic & covalent-type bonding.
Why do ceramics have larger bonding energy?
There is no perfect material?
How an LCD works
Pure Semiconductors: Conductivity vs. T
10. ...occurs in bcc metals but not in fcc metals.
Plastic Deformation (Metals)
Response to a Magnetic Field
Where does DBTT occur?
High impact energy
11. Cracks pass through grains - often along specific crystal planes.
Transgranular Fracture
Energy States: Insulators and Semiconductors
Thermal Expansion: Asymmetric curve
Brittle Fracture
12. 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.
Heat Capacity
Insulators
Yield and Reliability
Ductile-to-Brittle Transition
13. They are used to assess properties of ceramics & glasses.
Opacity
Diamagnetic Materials
Not severe
Bending tests
14. 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
Hysteresis and Permanent Magnetization
Scattering
Heat Capacity from an Atomic Prospective
Energy States: Insulators and Semiconductors
15. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Reflection of Light for Metals
Response to a Magnetic Field
Specific Heat
Ductile Fracture
16. Elastic means reversible! This is not a permanent deformation.
Shear and Tensile Stress
Thermal Expansion: Asymmetric curve
Elastic Deformation
Film Deposition
17. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
Force Decomposition
Large Hardness
Impact energy
Magnetic Storage
18. Diffuse image
HB (Brinell Hardness)
Thermal Expansion: Asymmetric curve
Translucent
Generation of a Magnetic Field - Within a Solid Material
19. Materials change size when temperature is changed
Plastic Deformation (Metals)
Thermal expansion
Griffith Crack Model
Ductile Fracture
20. A high index of refraction (n value) allows for multiple internal reactions.
Opacity
Brittle Fracture
Metallization
Sparkle of Diamonds
21. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
HB (Brinell Hardness)
Yield and Reliability
Modulus of Rupture (MOR)
Opacifiers
22. 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.
Thermal Stresses
Plastic Deformation (Metals)
Brittle Ceramics
Refraction
23. 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
Magnetic Storage
Luminescence examples
Iron-Silicon Alloy in Transformer Cores
24. Resistance to plastic deformation of cracking in compression - and better wear properties.
Soft Magnetic Materials
Film Deposition
Large Hardness
Hardness
25. 1. General yielding occurs if flaw size a < a(critical) 2. Catastrophic fast fracture occurs if flaw size a > a(critical)
M is known as what?
Engineering Fracture Performance
Brittle Ceramics
Reflection of Light for Metals
26. With Increasing temperature - the saturation magnetization diminishes gradually and then abruptly drops to zero at Curie Temperature - Tc.
Heat Capacity from an Atomic Prospective
Influence of Temperature on Magnetic Behavior
Pure Semiconductors: Conductivity vs. T
Impact - Toughness
27. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.
Translucent
Luminescence examples
The three modes of crack surface displacement
Lithography
28. 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
Critical Properties of Superconductive Materials
Metals: Resistivity vs. T - Impurities
True Stress
29. The ability of a material to transport heat - Atomic Perspective: Atomic vibrations and free electrons in hotter regions transport energy to cooler regions - Metals have the largest values
Luminescence examples
Brittle Fracture
True Strain
Thermal Conductivity
30. # of thermally generated electrons = # of holes (broken bonds)
Extrinsic Semiconductors
Intrinsic Semiconductors
Reflection of Light for Metals
M is known as what?
31. 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
Metallization
How to gage the extent of plastic deformation
Specific Heat
Impact - Toughness
32. Typical loading conditions are _____ enough to break all inter-atomic bonds
Ductile-to-Brittle Transition
Not severe
Reflection of Light for Metals
Opaque
33. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
There is no perfect material?
Yield and Reliability
Brittle Ceramics
Brittle Fracture
34. 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.
IC Devices: P-N Rectifying Junction
How an LCD works
Opaque
Translucent
35. High toughness; material resists crack propagation.
High impact energy
Stress Intensity values
Hard Magnetic Materials
What do magnetic moments arise from?
36. 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.
Thermal Conductivity
Brittle Ceramics
Ductile-to-Brittle Transition
Large Hardness
37. A measure of the ease with which a B field can be induced inside a material.
Relative Permeability
Modulus of Rupture (MOR)
Magnetic Storage
Heat Capacity
38. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Critical Properties of Superconductive Materials
Domains in Ferromagnetic & Ferrimagnetic Materials
Extrinsic Semiconductors
Yield and Reliability
39. 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
Oxidation
Influence of Temperature on Magnetic Behavior
Stress Intensity Factor
Where does DBTT occur?
40. Process by which metal atoms diffuse because of a potential.
Modulus of Rupture (MOR)
Why do ceramics have larger bonding energy?
Electromigration
How to gage the extent of plastic deformation
41. Measures Hardness - No major sample damage - Each scales runs to 130 but only useful in range 20-100 - Minor load is 10 kg - Major load: 60 kg (diamond) - 100 kg (1/16 in. ball) - 150 kg (diamond)
Stress Intensity Factor
Energy States: Insulators and Semiconductors
Rockwell
Intergranular Fracture
42. 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
Magnetic Storage
Brittle Ceramics
Hardness
Linewidth
43. If a material has ________ - then the field generated by those moments must be added to the induced field.
Pure Semiconductors: Conductivity vs. T
Generation of a Magnetic Field - Vacuum
Hard Magnetic Materials
Internal magnetic moments
44. Second phase particles with n > glass.
True Stress
Transparent
Opacifiers
There is no perfect material?
45. There is always some statistical distribution of flaws or defects.
There is no perfect material?
Luminescence
Slip Bands
Scattering
46. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Scattering
Generation of a Magnetic Field - Within a Solid Material
Valence band
Thermal Stresses
47. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
The three modes of crack surface displacement
IC Devices: P-N Rectifying Junction
High impact energy
Coefficient of Thermal Expansion
48. The size of the material changes with a change in temperature - polymers have the largest values
Transgranular Fracture
Hardness
Generation of a Magnetic Field - Within a Solid Material
Coefficient of Thermal Expansion
49. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Thermal Expansion: Asymmetric curve
Two ways to measure heat capacity
True Stress
Why materials fail in service
50. Ohms Law: voltage drop = current * resistance
Brittle Materials
Electrical Conduction
Metallization
Energy States: Insulators and Semiconductors