Mat Sci Midterm 1

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Mat Sci Midterm 1
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2012-04-24 13:49:56
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Midterm 1
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  1. a mixture of metals
    alloy
  2. study of what makes materials behave the way they do
    materials science
  3. to design new ways of intentionally altering the microstructure of materials to change properties
    materials engineering
  4. potential names for the current "age"
    uranium, silicon, plastics
  5. The Scientific Method
    Observation->Hypothesis->Experiement
  6. Oberserved the season in 16th century and hypothesized that smaller bodies orbit larger bodies
    Copernicus
  7. 17th century- experimented using the new Dutch telescope. Used moons of Saturn to confirm theory
    Galileo
  8. In racquet ball experiment:
    cold made ball-
    heat made plastic-
    • brittle->shattered
    • melt
    • *polymers get brittle when cold, metl when hot
  9. Engineering Design
    Analysis->Design->Fabrication
  10. Material Scientists-
    Material Engineers-
    • Explorers
    • Problem Solvers
  11. Material Science and Engineering Paradigm
    • Processing->Structure->Properties
    • Material Science= top down
    • Engineering= bottom up
  12. Product Structure Engineering Paradigm
    Materials (Properties)->Products/Structures->Performance
  13. Materials Processing
    • Composition->Mixing->Firing (forming after mixing, during firing after firing)
    • =Materials (Properties)
  14. Ways of creating new materials
    • 1. Combining elements- combinatorics, combinational synthesis
    • 2. Engineered materials- modifying existing materials
  15. Substance which cannot be resolved by chemical means into simpler substances
    element
  16. the number of electrons and protons an element contains
    atomic number
  17. a material that will conduct electricity without resistance below a certain temperature
    Super Conductor
  18. Uses of superconductors
    • magnetic levitation
    • magnetic resonance imaging
    • electricity generators- super conducting wires
    • energy storage systems for power stability
  19. super conductor found in 1987 at UA Huntsville
    first superconductor to work above temperature of liquid nitrogen (-196 C)
    YBCO
  20. Intentional Addition of imputities
    Doping
  21. _______ are generally formed form melts
    _______ generally formed from powders
    • metals
    • ceramics
  22. Classes of Materials
    ceramics, metals, polymers, biomaterials, semiconductors, composites, nanomaterials
  23. form of carbon that is:
    transparent, colorless, crystalline, very hard
    electrical insulator
    good conductor of heat
    Diamond
  24. Form of carbon that is:
    opaque, black, crystalline, slippery/soft
    very strong and stiff in one plane (covalent bonds), van der Waals in other
    good conductor of heat and electricity
    good lubricant
    Graphite
  25. Graphite and Diamond have the same
    atomic structure
  26. Graphite and Diamond have different
    electronic and crystal structure
  27. Smallest level of structure
    deals with bonding arrangements
    Electronic
  28. 2nd smallest level of structure
    deals with atom composition
    atomic structure
  29. level of structure dealing with the arrangement of atoms in space
    crystal structure
  30. level of structure that you need a microscope to see-
    characteristics of small crystals (ex: flaws in diamonds)
    microstructure
  31. largest level of structure, can be seen with the naked eye
    shape, size
    macrostructure
  32. width of a thumb nail
    millimeters
  33. width of human hair
    100 micrometers
  34. atoms around .1 ______meters
    nanometers
  35. crystals whose three axes are about the same in shape
    equiaxed microstructure
  36. boron gives diamond _____ color
    blue
  37. nitrogen give diamon _______ color
    yellow
  38. form of carbon
    is impure, no crystal structure, amorphous
    soot
  39. forrm of carbon that is purified soot
    used in inks, cosmetics, licorice, reinforces tires
    has microstructure of malted milkballs strung together
    carbon black
  40. form of carbon
    often used in sproting good items
    high stiffness, lightweight
    carbon fibers
  41. the basis of modern electronics
    makes up 25% of Earth's surface
    has 4 valence electrons
    same crystal structure as diamond but different electronic
    *opaque, shiny/metallic luster--> bonds not as strong as diamond
    silicon
  42. the only level of structure we cannot change
    crystal
  43. Material that is:
    opaque, lustrous/shiny, some are colored
    generally strong, ductile, malleable
    excellent conductors of heat and electricity
    some are magnetic but most no
    made up of elements or alloys, generally crystalline
    Metals
  44. Material that is:
    transparent or white, but can be colored
    Brittle, hard, refractory (high-melting)
    Insulating
    Some are magnetic
    Made of compounds, usually crystalline
    Ceramics
  45. Material that is transparent, amorphous
    has many similar traits to ceramics
    Glass
  46. Material that is:
    transparent, can be white or colored
    Deformable and tough ("plastic")
    made up of many units
    usually a long chain with carbon backbone
    Not magnetic
    Insulating
    Polymers
  47. Plastic that is flexible with heat
    Plastic that is brittle when heated
    • Thermoplastics
    • Thermosets
  48. Material that is:
    opaque, black (some colored), shiny
    Brittle
    Intermediate conductors
    Not magnetic
    Generally made of column 4 elements
    Semiconductors
  49. Common metals that are magnetic-
    nickel, iron, cobalt
  50. metal that is not a good conductor
    stainless steel
  51. a non-viable (non-living) material typically used in a medical device and intended to interact with biological systems
    (biocompatible)
    Biomaterials
  52. Type of biomaterial designed not to interact with tissue
    around the 1950s
    Bioinert
  53. Biomaterials that are resorbable (temporary- accomplish function then are resorbed in body) materials for drug delivery and bone bonding
    Around the 1980s
    Bioactive Materials
  54. Biomaterials for temporary or permanent scaffolds for tissue repair and advance therapeutics (drug-delivery systems)
    2000s
    Tissue Engineering
  55. Type of Biomaterial:
    Contacts:
    Cochlear Implant:
    Stent in artery wall:
    Joint replacements
    • -bioinert
    • -bioinert
    • -bioinert
    • -bioinert
  56. Biomaterials involve intersection of these three disciplines:
    • Material Science and Engineering
    • Biology
    • Medicine
  57. type of biomaterial that imitates biology
    • Biomemetics
    • ex: velcro and cockleburs
  58. The columns of the periodic table represent the number of _________
    valence electrons
  59. the maximum number of electrons
    • 2n2
    • n= number of the shell
  60. Type of bond that uses pool of free electrons
    -negative electrons (sea of elctrons) hold together positive cations through electrostatic attraction
    heat eventually breaks these bonds
    generally strong bonds
    ***not directional
    can pack closely
    canb move/change form pretty easily
    Metallic
  61. Type of bond in which atoms share electons (time sharing)
    **directional bonds
    cannot pack as closely-> not as dense
    don't deform as easily as metals, not as mobile
    *don't conduct electricity because no free electrons
    *strongest bonds
    generally 4 outer electrons
    Covalent Bonds
  62. Type of primary bond that features transfer of valence electrons from catioin to anion
    *insulators because of no free electrons
    *strong electrostatic bonds-
    *Non directional
    *close packing->dense
    anion is generally larger than the catio
    Ionic Bonding
  63. Secondary Bond that features polar molecules
    *permanent dipoles-> neg on one end, pos on teh other
    105 degree angle close to hexagon shape
    **Directional Bonds
    weak bonds between molecules
    Common in polymers
    Hydrogen Bonds
  64. Secondary bond featuring fluctuating dipoles
    weakest of all chemical bonds
    *solid ineart gases all are this type of bond
    **Non-directional
    explains lubricity of graphite
    van der Waals
  65. The two directional bonds
    Covalent, hydrogen
  66. Types of Primary Bonds that are insulators:
    Conductors:
    • Ionic, covalent
    • Metallic
  67. Bond Strengths
    • Covalent>Ionic>Metallic>Hydrogen>van der Waals
    • GENERALLY
  68. Heat conduction:
    uses free electrons which move between each other
    example was a pellet gun
    Electrons
  69. Type of heat conduction:
    Atom waves
    Phonons
  70. Type of heat conduction:
    knockons
    Vibrations
  71. Metals can conduct heat by:
    • Electrons
    • Phonons
    • Knockons
  72. Ceramics can conduct heat by:
    • Phonons
    • Knockons
  73. Polymers can conduct heat through
    Vibrations (knockons)
  74. Best to worst conductors
    Metals>Ceramics>Polymers
  75. technique that uses an x-ray through a material00> can creat dots at specific angles
    X-ray crystallography
  76. Packing strucutre that uses triangles
    has coordination number of 12
    Packing factor of .74
    12 slip systems
    4 non parallel slip planes
    also FCC
    • Cubic close packed
    • CCP
  77. packing pattern of CCP
    ABCABCABC...
  78. Packing structure that features hexagons
    Coordination factor= 12
    Packign factor=.74
    Has 3 slip systems
    • HCP
    • Hexagonal close packed
  79. Packing pattern of HCP
    ABABABABAB...
  80. examples of this packing structure:
    Helium, cadmium, titanium, magnesium, zinc, cobalt, ziranium
    HCP
  81. examples of this packing structrue are:
    Argon, neon, gold, silver, copper, aluminum, iron, nickel
    CCP
  82. Packing patter with coordination # of 8
    Packing factor=.68
    has more interstices, but they are smaller
    12 slip systems (6 planes, 2 directions)
    As ductile as CCP
    • BCC
    • Body Centered Cubic
  83. when a material can crystallize in different crystal structures
    Polymorhphism
  84. Silicon and Diaond have this type of packing stucture
    FCC
  85. Material that has different properties in different directions
    anisotropic
  86. For polycrystalline materials to be ductile, must have at least __ slip systems!
    • Von Mises' Criterion
    • 5
  87. ________ structure has short and long range order
    Crystalline
  88. _________ structure only has short range order
    Amorphous
  89. the simplest polymer
    Polyethylene
  90. Lots of metal elements mixed up-> cooled to fast so they don't have time to crystallize-> glassy, no grain boundaries, hard to break apart
    Bulk metallic glasses
  91. an amorphous solid
    glass
  92. process of heating glassy material to a temperature where the atoms begin to move around and arrange themselves in crystals
    devitrification
  93. these type of metals can only magnetize in one direction
    amorphous metals
  94. 0 D defects
    point defects
  95. 1 D defects
    Dislcations
  96. 2 D Defects
    Grain boundaries, surfaces
  97. 3 D Defects
    Precipitates, pores, inclusions
  98. Type of point defect which comes form the material itself
    Intrinsic point defect
  99. Types of intrinsic point defects
    • Vacancy
    • Self-Intersertial (energetically unfavorable)
    • vacancies more common (require less energy)
  100. Types of extrinsic point defects
    • Impurity intersertial
    • Substitutional- replacement
  101. when you can keep replacing one element with another until the material is entirely of the new material
    solid-solubility
  102. For silicon to be semiconductor grade it must only have impurities in ______
    1 part per billion
  103. Process of melting and reolidifying a solid as it passes through molten zone
    *the impurity atom in liquid state choses to stay in that form as metal solidifies
    zone-refining
  104. Molten metal iodides with different boiling temperatures separted
    Distillation
  105. Process in which pure metal iodide gas is reduced to metal
    Chemical Vapor Deposition
  106. Two types of dislocations
    • Edge dislocation
    • Screw dislocation
  107. Type of deformatio that is permaent:
    Not permanent:
    • Plastic
    • Elastic
  108. Stress=
    • Force/Area
    • measured in pounds per square inch
  109. Strain=
    • Change in Length/ Original Length
    • A unitless measure- percent
  110. Young's Modules
    Stiffness
  111. Young's Modules
    =Stiffness= Stress/Strain
  112. Types of stress
    • Tension (pulling)
    • Compressiong (pushing)
    • Shear (twisting)
  113. Ultimate Tensile Strength
    Weight at which material breaks/Cross Sectional Area
  114. The load required for plastic deformation to begin
    usually a .2% strain
    Yield Strength
  115. How to strengthen materials:
    • Work-hardening
    • Grain Refining
    • Substiutional Atoms (Solid Solution hardening)
    • Precipitates
  116. Way to strengthen materials that calls for adding dislocations
    the dislocations get tangled impeding movement
    Work Hardenening
  117. Type of strengthening that uses substitutional atoms to pin dislocations
    Susbsitutional Atoms, solid Solution hardening
  118. Way to strengthen by making grains smaller
    Grain refining
  119. Way to strengten in which precipitates form
    Precipitate strengthening
  120. this process repairs dislocations with heat
    annealing
  121. durning annealing atoms move around enough to produce new and more perfect crystals
    recrystallization
  122. the phase boundary
    solubility limit
  123. as precipitates age, they get too ________- and are less effective at impeding dislocatio movement
    large
  124. mold shaped like bottle, glob plastic inside, air blown in, plastic gets blown into shape of mold
    Parison Mold
  125. the study of "flow"
    rheology
  126. a half conductor
    hableiter
  127. this type of heat conduction needs crystalline structure
    phonon
  128. polymer grains
    spherullites
  129. dislocation in a polymer
    disclination
  130. What is used during xray crystallography
    difraction
  131. If you have no grain boundaries you have no _________
    weaknesses
  132. polymers have ________ which forms some crystalline regions
    chain folding
  133. From sugar disolving demo
    sovent=
    solute-
    • water
    • sugar
  134. Rank thermal expansion from smallest to largest
    ceramics<metals<polymers

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