lecture 2.2. classification of materials ii: the (microscopic) structure of materials from the...
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CLASSIFICATION OF MATERIALS II:CLASSIFICATION OF MATERIALS II:THE (MICROSCOPIC) STRUCTURE OF MATERIALSTHE (MICROSCOPIC) STRUCTURE OF MATERIALS
From the Sublime to the From the Sublime to the Ridiculous!Ridiculous!
THE MICROSCOPESTHE MICROSCOPES
The Light MicroscopeThe Light MicroscopeThe Scanning Electron Microscope (SEM)The Scanning Electron Microscope (SEM)The Transmission Electron Microscope The Transmission Electron Microscope
(TEM)(TEM)The Atomic Force Microscope (AFM)The Atomic Force Microscope (AFM)The Field-Ion Microscope (FIM)The Field-Ion Microscope (FIM)
THE SPACE SHUTTLETHE SPACE SHUTTLE
The skin of the Space Shuttle must withstand The skin of the Space Shuttle must withstand temperatures in excess of 1200˚Ctemperatures in excess of 1200˚C
The “tiles” are made from a silica (SiOThe “tiles” are made from a silica (SiO22) glass) glass Amorphous Ceramic/GlassAmorphous Ceramic/Glass
THE SPACE SHUTTLE TILETHE SPACE SHUTTLE TILE
SEM image of the SEM image of the silica (SiOsilica (SiO22) fibers) fibers Non-MetallicNon-Metallic InorganicInorganic AmorphousAmorphous SyntheticSynthetic CeramicCeramic
Amorphous Ceramic/GlassAmorphous Ceramic/Glass
THE MACROSTRUCTURE OF A THE MACROSTRUCTURE OF A DIAMONDDIAMOND
SEM Image (false color) of a SEM Image (false color) of a small, synthetic diamondsmall, synthetic diamond
The shape of the diamond is The shape of the diamond is an “octahedron”an “octahedron”
Many naturally occurring Many naturally occurring diamonds are also diamonds are also octahedral.octahedral.
Non-MetallicNon-Metallic InorganicInorganic CrystallineCrystalline SyntheticSynthetic Ceramic Ceramic
Crystalline CeramicCrystalline Ceramic
GRAPHITE: AN UNUSUAL GRAPHITE: AN UNUSUAL CERAMICCERAMIC
A Non-Metallic, A Non-Metallic, Elemental SolidElemental Solid
Non-MetallicNon-MetallicInorganicInorganicCrystallineCrystallineNaturalNaturalCeramicCeramic
Crystalline Ceramic:Crystalline Ceramic:Natural CeramicNatural Ceramic
THE ODESSA METEORITETHE ODESSA METEORITE Iron-nickel (~95%fe - 5%ni)Iron-nickel (~95%fe - 5%ni) Scanning electron microscope Scanning electron microscope
(SEM) image(SEM) image Two different polymorphs of Two different polymorphs of
iron: austenite and ferriteiron: austenite and ferrite Note the Note the scale markerscale marker The finger-like mixture of The finger-like mixture of
austenite and ferrite is called austenite and ferrite is called plessiteplessite
MetallicMetallic InorganicInorganic CrystallineCrystalline Naturally OccurringNaturally Occurring MetalMetal
Native Metal/Crystalline MetalNative Metal/Crystalline Metal
SECTIONED ALUMINUM CASTINGSECTIONED ALUMINUM CASTING
The casting solidified or The casting solidified or “crystallized” from the “outside-in”“crystallized” from the “outside-in”
The casting is “polycrystalline”, The casting is “polycrystalline”, The term “polycrystalline” means The term “polycrystalline” means
“consisting of many small, “consisting of many small, differently oriented differently oriented grains, grains, or or crystals”crystals”
MetallicMetallic InorganicInorganic CrystallineCrystalline SyntheticSynthetic MetalMetal
Crystalline MetalCrystalline Metal
BRONZE (COPPER-TIN) BRONZE (COPPER-TIN) POWDERPOWDER
SEM image of SEM image of bronze powderbronze powder
MetallicMetallic InorganicInorganic CrystallineCrystalline SyntheticSynthetic MetalMetal
Crystalline MetalCrystalline Metal
PARTIALLY SINTERED STEELPARTIALLY SINTERED STEEL
Steel: iron with ~ 0.8% Steel: iron with ~ 0.8% carboncarbon
Light micrographLight micrograph The powder particles The powder particles
have begun to sinterhave begun to sinter There is much “residual There is much “residual
porosity”porosity” MetallicMetallic InorganicInorganic CrystallineCrystalline SyntheticSynthetic MetalMetal
Crystalline MetalCrystalline Metal
““DISLOCATIONS” IN DISLOCATIONS” IN ALUMINUMALUMINUM
A “transmission electron A “transmission electron microscope” (TEM) image of microscope” (TEM) image of dislocations in aluminumdislocations in aluminum
Dislocations are “atomic-scale” Dislocations are “atomic-scale” defects that disrupt the crystalline defects that disrupt the crystalline perfection of the aluminumperfection of the aluminum
MetallicMetallic CrystallineCrystalline MetalMetal SyntheticSynthetic MetalMetal
Crystalline MetalCrystalline Metal
IMAGES OF ATOMS IIMAGES OF ATOMS I
Field-ion microscope (FIM) Field-ion microscope (FIM) image of atoms of tungstenimage of atoms of tungsten
Each “bright spot” corresponds Each “bright spot” corresponds to a tungsten atomto a tungsten atom
The atom was first “seen” at The atom was first “seen” at Penn State, in the 1950s, by Penn State, in the 1950s, by professor Irwin Muellerprofessor Irwin Mueller
Note that the tungsten is Note that the tungsten is crystalline.crystalline.
MetallicMetallic InorganicInorganic CrystallineCrystalline SyntheticSynthetic MetalMetal
Crystalline MetalCrystalline Metal
IMAGES OF ATOMS IIIMAGES OF ATOMS II
Atomic force Atomic force microscope (AFM) microscope (AFM) image of gold atomsimage of gold atoms
MetallicMetallic InorganicInorganic CrystallineCrystalline SyntheticSynthetic MetalMetal
Crystalline MetalCrystalline Metal
POLYPROPYLENEPOLYPROPYLENE
Light microscope image of Light microscope image of polypropylenepolypropylene
The thin polymer film was The thin polymer film was crystallized from an initially crystallized from an initially amorphous filmamorphous film
Each “crystal” is seen to Each “crystal” is seen to radiate from a “nucleation site,” radiate from a “nucleation site,” until adjacent crystals impingeuntil adjacent crystals impinge
Non-metallicNon-metallic OrganicOrganic CrystallineCrystalline SyntheticSynthetic PolymerPolymer
200µm
Crystalline PolymerCrystalline Polymer
HIGH DENSITY HIGH DENSITY POLYETHYLENEPOLYETHYLENE
Light microscope image of Light microscope image of “high density polyethylene” “high density polyethylene” (HDPE)(HDPE)
The thin polymer film was The thin polymer film was crystallized from an initially crystallized from an initially amorphous (LDPE) filmamorphous (LDPE) film
Each “crystal” is seen to Each “crystal” is seen to radiate from an “nucleation radiate from an “nucleation site,” until adjacent crystals site,” until adjacent crystals impingeimpinge
Non-MetallicNon-Metallic OrganicOrganic CrystallineCrystalline SyntheticSynthetic PolymerPolymer
Crystalline PolymerCrystalline Polymer
CASHMERECASHMERE
SEM image of a single SEM image of a single thread of cashmerethread of cashmere
Non-MetallicNon-Metallic OrganicOrganic Crystalline (?)Crystalline (?) NaturalNatural PolymerPolymer
Natural Polymer/Crystalline PolymerNatural Polymer/Crystalline Polymer
THE COLUMNS OF STEIDLE THE COLUMNS OF STEIDLE BUILDING IBUILDING I
The columns of Steidle The columns of Steidle Building are constructed Building are constructed from “drums” of sandstonefrom “drums” of sandstone
Sandstone is a naturally Sandstone is a naturally occurring compositeoccurring composite
Sandstone is also a ceramicSandstone is also a ceramic Sandstone is a rock!Sandstone is a rock!
Non-MetallicNon-Metallic InorganicInorganic CrystallineCrystalline Naturally OccurringNaturally Occurring Rock/CompositeRock/CompositeCeramic/Ceramic Composite:Ceramic/Ceramic Composite:
Natural Ceramic:Natural Ceramic:Crystalline CeramicCrystalline Ceramic
THE COLUMNS OF STEIDLE THE COLUMNS OF STEIDLE BUILDING IIBUILDING II
At low magnification, the At low magnification, the original sand (quartz) grains original sand (quartz) grains are seenare seen
The quartz grains are The quartz grains are somewhat less than 1mm in somewhat less than 1mm in sizesize
But what caused the sand to But what caused the sand to “lithify?” What material “lithify?” What material “sintered” the sand grains “sintered” the sand grains together? What is the together? What is the “cement” which binds the “cement” which binds the composite into a composite into a “monolithic” material?“monolithic” material?
THE COLUMNS OF STEIDLE THE COLUMNS OF STEIDLE BUILDING IIIBUILDING III
At high magnification, a “plate-like” phase is seen in the spaces At high magnification, a “plate-like” phase is seen in the spaces between the sand grains.between the sand grains.
The “cement” that sinters the sand grains together is called The “cement” that sinters the sand grains together is called Calcite: calcium carbonate (CaCOCalcite: calcium carbonate (CaCO33).).