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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 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
The three modes of crack surface displacement
Iron-Silicon Alloy in Transformer Cores
High impact energy
2. These materials are relatively unaffected by magnetic fields.
Domains in Ferromagnetic & Ferrimagnetic Materials
High impact energy
Diamagnetic Materials
Soft Magnetic Materials
3. 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.
Insulators
Refraction
Pure Semiconductors: Conductivity vs. T
Hysteresis and Permanent Magnetization
4. 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
Influence of Temperature on Magnetic Behavior
Film Deposition
How an LCD works
Energy States: Insulators and Semiconductors
5. Because of ionic & covalent-type bonding.
Shear and Tensile Stress
Pure Semiconductors: Conductivity vs. T
Ductile Materials
Why do ceramics have larger bonding energy?
6. The size of the material changes with a change in temperature - polymers have the largest values
Liquid Crystal Displays (LCD's)
Electromigration
Coefficient of Thermal Expansion
Conduction & Electron Transport
7. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Coefficient of Thermal Expansion
Generation of a Magnetic Field - Within a Solid Material
Bending tests
To improve fatigue life
8. The ability of a material to be rapidly cooled and not fracture
Oxidation
Not severe
Sparkle of Diamonds
Thermal Shock Resistance
9. 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.
Iron-Silicon Alloy in Transformer Cores
Luminescence
Plastic Deformation (Metals)
Impact - Toughness
10. These are liquid crystal polymers- not your normal "crystal" -Rigid - rod shaped molecules are aligned even in liquid form.
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11. Different orientation of cleavage planes in grains.
Heat Capacity from an Atomic Prospective
Why fracture surfaces have faceted texture
Pure Semiconductors: Conductivity vs. T
Scattering
12. 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
Magnetic Storage Media Types
Energy States: Insulators and Semiconductors
Intrinsic Semiconductors
13. Small Coercivities - Used for electric motors - Example: commercial iron 99.95 Fe
How to gage the extent of plastic deformation
Valence band
Soft Magnetic Materials
Brittle Fracture
14. Cracks propagate along grain boundaries.
Work Hardening
The Transistor
Intergranular Fracture
Coefficient of Thermal Expansion
15. 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
Superconductivity
Elastic Deformation
4 Types of Magnetism
Luminescence
16. Dramatic change in impact energy is associated with a change in fracture mode from brittle to ductile.
Refraction
Ductile-to-Brittle Transition
Heat Capacity
Linewidth
17. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Modulus of Rupture (MOR)
Thermal expansion
Bending tests
Holloman Equation
18. 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.
M is known as what?
Modulus of Rupture (MOR)
Plastic Deformation (Metals)
Energy States: Insulators and Semiconductors
19. 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
Energy States: Insulators and Semiconductors
Brittle Materials
Magnetic Storage
Refraction
20. A high index of refraction (n value) allows for multiple internal reactions.
Valence band
Electrical Conduction
Sparkle of Diamonds
Conduction & Electron Transport
21. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Yield and Reliability
Work Hardening
Influence of Temperature on Magnetic Behavior
Extrinsic Semiconductors
22. Increase temperature - no increase in interatomic separation - no thermal expansion
Metals: Resistivity vs. T - Impurities
Thermal Expansion: Symmetric curve
Diamagnetic Materials
Heat Capacity from an Atomic Prospective
23. 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.
Ductile-to-Brittle Transition
Thermal Conductivity
Holloman Equation
Opaque
24. Degree of opacity depends on size and number of particles - Opacity of metals is the result of conduction electrons absorbing photons in the visible range.
Magnetic Storage Media Types
Rockwell
Brittle Fracture
Opacity
25. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Not severe
Generation of a Magnetic Field - Vacuum
Coefficient of Thermal Expansion
Incident Light
26. 1. Metals: Thermal energy puts many electrons into a higher energy state. 2. Energy States: Nearby energy states are accessible by thermal fluctuations.
There is no perfect material?
True Strain
Conduction & Electron Transport
Internal magnetic moments
27. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Thermal Shock Resistance
Luminescence examples
Pure Semiconductors: Conductivity vs. T
Ductile Fracture
28. Without passing a current a continually varying magnetic field will cause a current to flow
Oxidation
Magnetic Storage
Opaque
Response to a Magnetic Field
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
Generation of a Magnetic Field - Within a Solid Material
Brittle Materials
Thermal Conductivity
Impact energy
30. 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
Iron-Silicon Alloy in Transformer Cores
Hardness
Griffith Crack Model
Extrinsic Semiconductors
31. Process by which geometric patterns are transferred from a mask (reticle) to a surface of a chip to form the device.
Brittle Ceramics
Generation of a Magnetic Field - Within a Solid Material
Magnetic Storage Media Types
Lithography
32. Specific heat = energy input/(mass*temperature change)
Luminescence
Ductile Materials
Specific Heat
Conduction & Electron Transport
33. 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.
Opaque
Refraction
Scattering
Valence band
34. 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
Incoherent
Intergranular Fracture
Bending tests
35. High toughness; material resists crack propagation.
Specific Heat
Why materials fail in service
Slip Bands
High impact energy
36. If a material has ________ - then the field generated by those moments must be added to the induced field.
Diamagnetic Materials
Opacifiers
There is no perfect material?
Internal magnetic moments
37. Diffuse image
Linewidth
Translucent
Reflection of Light for Metals
M is known as what?
38. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Sparkle of Diamonds
Two kinds of Reflection
Ductile-to-Brittle Transition
Domains in Ferromagnetic & Ferrimagnetic Materials
39. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Brittle Fracture
Energy States: Insulators and Semiconductors
Luminescence examples
Diamagnetic Materials
40. A measure of the ease with which a B field can be induced inside a material.
Influence of Temperature on Magnetic Behavior
Relative Permeability
Charpy or Izod test
Magnetic Storage Media Types
41. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture
Metals: Resistivity vs. T - Impurities
Hard Magnetic Materials
Stages of Failure: Ductile Fracture
Work Hardening
42. Stress concentration at a crack tips
Griffith Crack Model
What do magnetic moments arise from?
Why do ceramics have larger bonding energy?
Yield and Reliability
43. Allows you to calculate what happened G=F' x cos(lambda) - F=F' x cos(phi)
True Stress
Critical Properties of Superconductive Materials
Opaque
Force Decomposition
44. Found in 26 metals and hundreds of alloys & compounds - Tc= critical temperature = termperature below which material is superconductive.
True Strain
Not severe
Incident Light
Superconductivity
45. 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.
What do magnetic moments arise from?
Hardness
To improve fatigue life
Diamagnetic Materials
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
Refraction
Stages of Failure: Ductile Fracture
Yield and Reliability
Ductile-to-Brittle Transition
47. Typical loading conditions are _____ enough to break all inter-atomic bonds
Work Hardening
Not severe
HB (Brinell Hardness)
Thermal Expansion: Symmetric curve
48. 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.
Hardness
Insulators
Reflectance of Non-Metals
Thermal Conductivity
49. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Valence band
Fatigue
Hardness
Transgranular Fracture
50. - 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
Plastic Deformation (Metals)
Thermal Conductivity
Impact - Toughness
Luminescence