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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. 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
High impact energy
Large Hardness
Two kinds of Reflection
2. These materials are relatively unaffected by magnetic fields.
Diamagnetic Materials
Fourier's Law
Brittle Ceramics
True Stress
3. 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.
Fourier's Law
Opacity
4 Types of Magnetism
Relative Permeability
4. 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.
Why fracture surfaces have faceted texture
Scattering
M is known as what?
High impact energy
5. 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
Brittle Materials
Soft Magnetic Materials
Iron-Silicon Alloy in Transformer Cores
Linewidth
6. 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
Refraction
Opacifiers
Stress Intensity Factor
Intrinsic Semiconductors
7. They are used to assess properties of ceramics & glasses.
Stress Intensity Factor
Bending tests
Work Hardening
Why do ceramics have larger bonding energy?
8. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Incident Light
Domains in Ferromagnetic & Ferrimagnetic Materials
Critical Properties of Superconductive Materials
Extrinsic Semiconductors
9. Increase temperature - no increase in interatomic separation - no thermal expansion
The three modes of crack surface displacement
Thermal Expansion: Symmetric curve
Thermal Shock Resistance
Color
10. Without passing a current a continually varying magnetic field will cause a current to flow
Diamagnetic Materials
Response to a Magnetic Field
Where does DBTT occur?
IC Devices: P-N Rectifying Junction
11. The size of the material changes with a change in temperature - polymers have the largest values
Generation of a Magnetic Field - Vacuum
Electromigration
Specific Heat
Coefficient of Thermal Expansion
12. 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
Lithography
Impact - Toughness
Ductile-to-Brittle Transition
Superconductivity
13. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Reflectance of Non-Metals
Diamagnetic Materials
Impact - Toughness
Fatigue
14. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))
Iron-Silicon Alloy in Transformer Cores
Brittle Materials
Film Deposition
True Stress
15. Typical loading conditions are _____ enough to break all inter-atomic bonds
Not severe
HB (Brinell Hardness)
Relative Permeability
Coefficient of Thermal Expansion
16. 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
Force Decomposition
Slip Bands
Brittle Ceramics
17. Increase temperature - increase in interatomic separation - thermal expansion
High impact energy
Thermal Expansion: Symmetric curve
Fatigue
Thermal Expansion: Asymmetric curve
18. Undergo little or no plastic deformation.
How to gage the extent of plastic deformation
Opacity
Brittle Materials
Scattering
19. 1. Insulators: Higher energy states NOT ACCESSIBLE due to gap 2. Semiconductors: Higher energy states separated by a smaller gap.
Large Hardness
Energy States: Insulators and Semiconductors
Thermal Expansion: Symmetric curve
Bending tests
20. Growing interconnections to connect devices -Low electrical resistance - good adhesion to dielectric insulators.
Metallization
Coherent
Two kinds of Reflection
Critical Properties of Superconductive Materials
21. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Where does DBTT occur?
IC Devices: P-N Rectifying Junction
Generation of a Magnetic Field - Within a Solid Material
Translucent
22. 1. Imperfections increase resistivity - grain boundaries - dislocations - impurity atoms - vacancies 2. Resistivity - increases with temperature - wt% impurity - and %CW
Charpy or Izod test
Yield and Reliability
Iron-Silicon Alloy in Transformer Cores
Metals: Resistivity vs. T - Impurities
23. Impurities added to the semiconductor that contribute to excess electrons or holes. Doping = intentional impurities.
Stress Intensity Factor
Meissner Effect
Yield and Reliability
Extrinsic Semiconductors
24. 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.
Critical Properties of Superconductive Materials
Thermal Expansion: Symmetric curve
Stress Intensity values
Hardness
25. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
HB (Brinell Hardness)
Heat Capacity
IC Devices: P-N Rectifying Junction
Relative Permeability
26. Process by which metal atoms diffuse because of a potential.
Thermal Stresses
The three modes of crack surface displacement
Electromigration
LASER
27. 1. Electron motions 2. The spins on electrons - Net atomic magnetic moment: sum of moments from all electrons.
Metallization
What do magnetic moments arise from?
High impact energy
Stages of Failure: Ductile Fracture
28. If a material has ________ - then the field generated by those moments must be added to the induced field.
Internal magnetic moments
Generation of a Magnetic Field - Within a Solid Material
Fatigue
Oxidation
29. Energy is stored as atomic vibrations - As temperature increases - the average energy of atomic vibrations increases.
Heat Capacity from an Atomic Prospective
Generation of a Magnetic Field - Within a Solid Material
Brittle Ceramics
Impact energy
30. 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
Opaque
Metallization
Thermal Expansion: Asymmetric curve
31. 1. Impose a compressive surface stress (to suppress surface cracks from growing) - Method 1: shot peening - Method 2: carburizing 2.Remove stress concentrators.
LASER
To improve fatigue life
Relative Permeability
HB (Brinell Hardness)
32. 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
Slip Bands
4 Types of Magnetism
How to gage the extent of plastic deformation
What do magnetic moments arise from?
33. -> fluorescent light - electron transitions occur randomly - light waves are out of phase with each other.
Thermal Shock Resistance
Incoherent
To improve fatigue life
Electromigration
34. There is always some statistical distribution of flaws or defects.
High impact energy
There is no perfect material?
Brittle Materials
Luminescence examples
35. Dimples on fracture surface correspond to microcavities that initiate crack formation.
Etching
Ductile Fracture
Thermal Stresses
Metals: Resistivity vs. T - Impurities
36. Becomes harder (more strain) to stretch (elongate)
Work Hardening
Thermal Expansion: Symmetric curve
Oxidation
Large Hardness
37. Resistance to plastic deformation of cracking in compression - and better wear properties.
Electrical Conduction
Thermal Expansion: Symmetric curve
Large Hardness
Yield and Reliability
38. 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
Yield and Reliability
Relative Permeability
Elastic Deformation
39. Undergo extensive plastic deformation prior to failure.
Ductile Materials
Domains in Ferromagnetic & Ferrimagnetic Materials
Rockwell
Meissner Effect
40. Is analogous to toughness.
Reflection of Light for Metals
Coherent
Impact energy
Brittle Materials
41. ...occurs in bcc metals but not in fcc metals.
Where does DBTT occur?
Brittle Fracture
Opacifiers
Why do ceramics have larger bonding energy?
42. Ohms Law: voltage drop = current * resistance
Heat Capacity from an Atomic Prospective
Coefficient of Thermal Expansion
Electrical Conduction
Incoherent
43. 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.
Ductile-to-Brittle Transition
Elastic Deformation
Shear and Tensile Stress
Diamagnetic Materials
44. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.
Two ways to measure heat capacity
Electromigration
Response to a Magnetic Field
Specific Heat
45. (sigma)=K(sigma)^n . K = strength coefficient - n = work hardening rate or strain hardening exponent. Large n value increases strength and hardness.
Holloman Equation
Shear and Tensile Stress
LASER
Intrinsic Semiconductors
46. 1. Necking 2. Cavity formation 3. Cavity coalescence to form cracks 4. Crack propagation (growth) 5. Fracture
Generation of a Magnetic Field - Vacuum
Insulators
Brittle Fracture
Stages of Failure: Ductile Fracture
47. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)
Shear and Tensile Stress
Two kinds of Reflection
Stress Intensity values
True Stress
48. These materials are "attracted" to magnetic fields.
Two kinds of Reflection
Thermal Expansion: Asymmetric curve
Paramagnetic Materials
Yield and Reliability
49. This strength parameter is similar in magnitude to a tensile strength. Fracture occurs along the outermost sample edge - which is under a tensile load.
Modulus of Rupture (MOR)
Color
Incoherent
Bending tests
50. 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.
Scattering
Influence of Temperature on Magnetic Behavior
Magnetic Storage
Transgranular Fracture