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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. Flaws and Defects - They concentrate stress locally to levels high enough to rupture bonds.
Thermal Stresses
Why materials fail in service
Extrinsic Semiconductors
Hardness
2. Large coercivities - Used for permanent magnets - Add particles/voids to inhibit domain wall motion - Example: tungsten steel
Hard Magnetic Materials
Hysteresis and Permanent Magnetization
Metals: Resistivity vs. T - Impurities
Electrical Conduction
3. Allows flow of electrons in one direction only (useful to convert alternating current to direct current) - Result: no net current flow
Superconductivity
Large Hardness
Yield and Reliability
IC Devices: P-N Rectifying Junction
4. - A magnetic field is induced in the material B= Magnetic Induction (tesla) inside the material mu= permeability of a solid
Liquid Crystal Displays (LCD's)
Intrinsic Semiconductors
Force Decomposition
Generation of a Magnetic Field - Within a Solid Material
5. There is always some statistical distribution of flaws or defects.
Incident Light
There is no perfect material?
Why materials fail in service
Thermal Conductivity
6. Specific heat = energy input/(mass*temperature change)
Rockwell
Reflection of Light for Metals
Specific Heat
Not severe
7. 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.
Opaque
There is no perfect material?
Incoherent
Refraction
8. They are used to assess properties of ceramics & glasses.
Relative Permeability
Bending tests
Shear and Tensile Stress
Luminescence examples
9. Measures impact energy 1. Strike a notched sample with an anvil 2. Measure how far the anvil travels following impact 3. Distance traveled is related to energy required to break the sample 4. Very high rate of loading. Makes materials more "brittle."
Diamagnetic Materials
LASER
Charpy or Izod test
To improve fatigue life
10. Undergo extensive plastic deformation prior to failure.
Ductile Materials
M is known as what?
Domains in Ferromagnetic & Ferrimagnetic Materials
Incident Light
11. 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)
Rockwell
Stages of Failure: Ductile Fracture
Yield and Reliability
Why do ceramics have larger bonding energy?
12. Ability to transmit a clear image - The image is clear.
Thermal Conductivity
Transparent
High impact energy
Ductile-to-Brittle Transition
13. These materials are "attracted" to magnetic fields.
Paramagnetic Materials
Stages of Failure: Ductile Fracture
Force Decomposition
Dependence of Heat Capacity on Temperature
14. For a metal - there is no ______ - only reflection
Oxidation
Refraction
IC Devices: P-N Rectifying Junction
Stages of Failure: Ductile Fracture
15. (sigma)=F/Ai (rho)=(rho)'(1+(epsilon))
Conduction & Electron Transport
Impact - Toughness
True Stress
Dependence of Heat Capacity on Temperature
16. Second phase particles with n > glass.
Thermal Stresses
Opacifiers
Influence of Temperature on Magnetic Behavior
Iron-Silicon Alloy in Transformer Cores
17. 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.
Elastic Deformation
Heat Capacity
Shear and Tensile Stress
Stress Intensity Factor
18. 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
Why fracture surfaces have faceted texture
4 Types of Magnetism
Ductile Materials
19. 1. Data for Pure Silicon - electrical conductivity increases with T - opposite to metals
Extrinsic Semiconductors
Pure Semiconductors: Conductivity vs. T
Conduction & Electron Transport
Heat Capacity from an Atomic Prospective
20. 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
Magnetic Storage Media Types
The Transistor
Response to a Magnetic Field
Opacity
21. 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
Large Hardness
Refraction
Incident Light
Two kinds of Reflection
22. Different orientation of cleavage planes in grains.
Fatigue
Magnetic Storage
Relative Permeability
Why fracture surfaces have faceted texture
23. Increase temperature - no increase in interatomic separation - no thermal expansion
Thermal Expansion: Symmetric curve
Metals: Resistivity vs. T - Impurities
There is no perfect material?
Translucent
24. Cp: Heat capacity at constant pressure Cv: Heat capacity at constant volume.
Two ways to measure heat capacity
Thermal Conductivity
Incident Light
How an LCD works
25. 1. Tensile (opening) 2. Sliding 3. Tearing
Reflection of Light for Metals
The three modes of crack surface displacement
Thermal Expansion: Symmetric curve
Specific Heat
26. Is analogous to toughness.
Not severe
Transgranular Fracture
Impact energy
IC Devices: P-N Rectifying Junction
27. Materials change size when temperature is changed
The three modes of crack surface displacement
Magnetic Storage Media Types
Thermal expansion
Energy States: Insulators and Semiconductors
28. Because of ionic & covalent-type bonding.
Engineering Fracture Performance
True Stress
Hard Magnetic Materials
Why do ceramics have larger bonding energy?
29. The ability of a material to be rapidly cooled and not fracture
Thermal Conductivity
Opaque
Thermal Shock Resistance
Linewidth
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
Film Deposition
Lithography
Charpy or Izod test
Iron-Silicon Alloy in Transformer Cores
31. - 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
Insulators
Coefficient of Thermal Expansion
M is known as what?
Luminescence
32. The size of the material changes with a change in temperature - polymers have the largest values
Coefficient of Thermal Expansion
Holloman Equation
Energy States: Insulators and Semiconductors
Dependence of Heat Capacity on Temperature
33. 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
4 Types of Magnetism
HB (Brinell Hardness)
Lithography
Brittle Fracture
34. Specular: light reflecting off a mirror (average) - Diffuse: light reflecting off a white wall (local)
Valence band
Dependence of Heat Capacity on Temperature
Thermal Conductivity
Two kinds of Reflection
35. - 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
Two ways to measure heat capacity
Metals: Resistivity vs. T - Impurities
Energy States: Insulators and Semiconductors
Stress Intensity values
36. Light Amplification by Stimulated Emission of Radiation
IC Devices: P-N Rectifying Junction
Large Hardness
HB (Brinell Hardness)
LASER
37. 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.
Charpy or Izod test
Reflectance of Non-Metals
Sparkle of Diamonds
Shear and Tensile Stress
38. 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.
Iron-Silicon Alloy in Transformer Cores
Heat Capacity
Generation of a Magnetic Field - Vacuum
Why materials fail in service
39. Emitted light is in phase
To improve fatigue life
Dependence of Heat Capacity on Temperature
Magnetic Storage Media Types
Coherent
40. Measures Hardness 1. psia = 500 x HB 2. MPa = 3.45 x HB
Magnetic Storage
HB (Brinell Hardness)
Transparent
Liquid Crystal Displays (LCD's)
41. Occur due to: restrained thermal expansion/contraction -temperature gradients that lead to differential dimensional changes sigma = Thermal Stress
IC Devices: P-N Rectifying Junction
Thermal Stresses
Where does DBTT occur?
Domains in Ferromagnetic & Ferrimagnetic Materials
42. 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
Ductile-to-Brittle Transition
Critical Properties of Superconductive Materials
Magnetic Storage
Impact energy
43. Another optical property - Depends on the wavelength of the visible spectrum.
What do magnetic moments arise from?
Color
Domains in Ferromagnetic & Ferrimagnetic Materials
Intrinsic Semiconductors
44. 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
Fourier's Law
Energy States: Insulators and Semiconductors
Yield and Reliability
Translucent
45. Failure under cyclic stress 1. It can cause part failure - even though (sigma)max < (sigma)c 2. Causes ~90% of mechanical engineering failures.
Ductile Materials
Specific Heat
Hysteresis and Permanent Magnetization
Fatigue
46. No appreciable plastic deformation. The crack propagates very fast; nearly perpendicular to applied stress. Cracks often propagate along specific crystal planes or boundaries.
Reflection of Light for Metals
Relative Permeability
Opacity
Brittle Fracture
47. Is reflected - absorbed - scattered - and/or transmitted: Io=It+Ia+Ir+Is
Incident Light
Soft Magnetic Materials
Elastic Deformation
Force Decomposition
48. 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)
Stages of Failure: Ductile Fracture
Force Decomposition
Metals: Resistivity vs. T - Impurities
49. As the applied field (H) increases the magnetic domains change shape and size by movement of domain boundaries.
Domains in Ferromagnetic & Ferrimagnetic Materials
Etching
M is known as what?
Intrinsic Semiconductors
50. ...occurs in bcc metals but not in fcc metals.
Hardness
To improve fatigue life
Generation of a Magnetic Field - Within a Solid Material
Where does DBTT occur?