LECTURE 2.1

LECTURE OUTLINE Weekly Deadlines Weekly Deadlines Course/Lecture Philosophy Course/Lecture Philosophy The Microscopic Structure of Materials The Microscopic Structure of Materials Lesson 02 Prototype Quiz Lesson 02 Prototype Quiz

COURSE PHILOSOPHY To teach scientific literacy by fostering good (scientific) reading, writing and study habits. To teach scientific literacy by fostering good (scientific) reading, writing and study habits. The primary goal is not to teach materials science and engineering but to use principles of materials science to promote scientific literacy. The primary goal is not to teach materials science and engineering but to use principles of materials science to promote scientific literacy.

LECTURE PHILOSOPHY—OR WHAT PURPOSE IS SERVED BY THE LECTURES? MATSE 081 can be taken either wholly online, or as a blended online/in-class hybrid. MATSE 081 can be taken either wholly online, or as a blended online/in-class hybrid. For the online group, all of the course content is supplied either online, via videos and animations, or by the book. For the online group, all of the course content is supplied either online, via videos and animations, or by the book.

LECTURE PHILOSOPHY—OR WHAT PURPOSE IS SERVED BY THE LECTURES? If we make the assumption that all content may be delivered outside the lectures, then what role should the lectures play? If we make the assumption that all content may be delivered outside the lectures, then what role should the lectures play? The lectures should support the fundamental objective of the course: The lectures should support the fundamental objective of the course: To teach scientific literacy by fostering good (scientific) reading, writing and study habits. To teach scientific literacy by fostering good (scientific) reading, writing and study habits.

LECTURE PHILOSOPHY—OR WHAT PURPOSE IS SERVED BY THE LECTURES? Good reading and study habits are encouraged by the open-book quizzes, and the in-class practice quizzes. Good reading and study habits are encouraged by the open-book quizzes, and the in-class practice quizzes. Good scientific writing is promoted by the discussion in class of scientific essay components. Good scientific writing is promoted by the discussion in class of scientific essay components.

CLASSIFICATION OF MATERIALS II: THE (MICROSCOPIC) STRUCTURE OF MATERIALS From the Sublime to the Ridiculous!

THE MICROSCOPES The Light Microscope The Light Microscope The Scanning Electron Microscope (SEM) The Scanning Electron Microscope (SEM) The Transmission Electron Microscope (TEM) The Transmission Electron Microscope (TEM) The Atomic Force Microscope (AFM) The Atomic Force Microscope (AFM) The Field-Ion Microscope (FIM) The Field-Ion Microscope (FIM)

THE SPACE SHUTTLE The skin of the Space Shuttle must withstand temperatures in excess of 1200˚C The skin of the Space Shuttle must withstand temperatures in excess of 1200˚C The “tiles” are made from a silica (SiO 2 ) glass The “tiles” are made from a silica (SiO 2 ) glass Amorphous Ceramic/Glass

THE SPACE SHUTTLE TILE SEM image of the silica (SiO 2 ) fibers SEM image of the silica (SiO 2 ) fibers Non-Metallic Inorganic Amorphous Synthetic Ceramic Amorphous Ceramic/Glass

THE MACROSTRUCTURE OF A DIAMOND SEM Image (false color) of a small, synthetic diamond SEM Image (false color) of a small, synthetic diamond The shape of the diamond is an “octahedron” The shape of the diamond is an “octahedron” Many naturally occurring diamonds are also octahedral. Many naturally occurring diamonds are also octahedral. Non-Metallic Inorganic Crystalline Synthetic Ceramic Crystalline Ceramic

GRAPHITE: AN UNUSUAL CERAMIC A Non-Metallic, Elemental Solid A Non-Metallic, Elemental Solid Non-Metallic Inorganic Crystalline Natural Ceramic Crystalline Ceramic: Natural Ceramic

THE ODESSA METEORITE Iron-nickel (~95%fe - 5%ni) Iron-nickel (~95%fe - 5%ni) Scanning electron microscope (SEM) image Scanning electron microscope (SEM) image Two different polymorphs of iron: austenite and ferrite Two different polymorphs of iron: austenite and ferrite Note the scale marker Note the scale marker The finger-like mixture of austenite and ferrite is called plessite The finger-like mixture of austenite and ferrite is called plessite Metallic Inorganic Crystalline Naturally Occurring Metal Native Metal/Crystalline Metal

SECTIONED ALUMINUM CASTING The casting solidified or “crystallized” from the “outside-in” The casting solidified or “crystallized” from the “outside-in” The casting is “polycrystalline”, The casting is “polycrystalline”, The term “polycrystalline” means “consisting of many small, differently oriented grains, or crystals” The term “polycrystalline” means “consisting of many small, differently oriented grains, or crystals” Metallic Inorganic Crystalline Synthetic Metal Crystalline Metal

BRONZE (COPPER-TIN) POWDER SEM image of bronze powder SEM image of bronze powder Metallic Inorganic Crystalline Synthetic Metal Crystalline Metal

PARTIALLY SINTERED STEEL Steel: iron with ~ 0.8% carbon Steel: iron with ~ 0.8% carbon Light micrograph Light micrograph The powder particles have begun to sinter The powder particles have begun to sinter There is much “residual porosity” There is much “residual porosity” Metallic Inorganic Crystalline Synthetic Metal Crystalline Metal

“DISLOCATIONS” IN ALUMINUM A “transmission electron microscope” (TEM) image of dislocations in aluminum A “transmission electron microscope” (TEM) image of dislocations in aluminum Dislocations are “atomic-scale” defects that disrupt the crystalline perfection of the aluminum Dislocations are “atomic-scale” defects that disrupt the crystalline perfection of the aluminum Metallic Crystalline Metal Synthetic Metal Crystalline Metal

IMAGES OF ATOMS I Field-ion microscope (FIM) image of atoms of tungsten Field-ion microscope (FIM) image of atoms of tungsten Each “bright spot” corresponds to a tungsten atom Each “bright spot” corresponds to a tungsten atom The atom was first “seen” at Penn State, in the 1950s, by professor Irwin Mueller The atom was first “seen” at Penn State, in the 1950s, by professor Irwin Mueller Note that the tungsten is crystalline. Note that the tungsten is crystalline. Metallic Inorganic Crystalline Synthetic Metal Crystalline Metal

IMAGES OF ATOMS II Atomic force microscope (AFM) image of gold atoms Atomic force microscope (AFM) image of gold atoms Metallic Inorganic Crystalline Synthetic Metal Crystalline Metal

POLYPROPYLENE Light microscope image of polypropylene Light microscope image of polypropylene The thin polymer film was crystallized from an initially amorphous film The thin polymer film was crystallized from an initially amorphous film Each “crystal” is seen to radiate from a “nucleation site,” until adjacent crystals impinge Each “crystal” is seen to radiate from a “nucleation site,” until adjacent crystals impinge Non-metallic Organic Crystalline Synthetic Polymer 200µm Crystalline Polymer

HIGH DENSITY POLYETHYLENE Light microscope image of “high density polyethylene” (HDPE) Light microscope image of “high density polyethylene” (HDPE) The thin polymer film was crystallized from an initially amorphous (LDPE) film The thin polymer film was crystallized from an initially amorphous (LDPE) film Each “crystal” is seen to radiate from an “nucleation site,” until adjacent crystals impinge Each “crystal” is seen to radiate from an “nucleation site,” until adjacent crystals impinge Non-Metallic Organic Crystalline Synthetic Polymer Crystalline Polymer

CASHMERE SEM image of a single thread of cashmere SEM image of a single thread of cashmere Non-Metallic Organic Crystalline (?) Natural Polymer Natural Polymer/Crystalline Polymer

THE COLUMNS OF STEIDLE BUILDING I The columns of Steidle Building are constructed from “drums” of sandstone The columns of Steidle Building are constructed from “drums” of sandstone Sandstone is a naturally occurring composite Sandstone is a naturally occurring composite Sandstone is also a ceramic Sandstone is also a ceramic Sandstone is a rock! Sandstone is a rock! Non-Metallic Inorganic Crystalline Naturally Occurring Rock/Composite Ceramic/Ceramic Composite: Natural Ceramic: Crystalline Ceramic

THE COLUMNS OF STEIDLE BUILDING II At low magnification, the original sand (quartz) grains are seen At low magnification, the original sand (quartz) grains are seen The quartz grains are somewhat less than 1mm in size The quartz grains are somewhat less than 1mm in size But what caused the sand to “lithify?” What material “sintered” the sand grains together? What is the “cement” which binds the composite into a “monolithic” material? But what caused the sand to “lithify?” What material “sintered” the sand grains together? What is the “cement” which binds the composite into a “monolithic” material?

THE COLUMNS OF STEIDLE BUILDING III At high magnification, a “plate-like” phase is seen in the spaces between the sand grains. At high magnification, a “plate-like” phase is seen in the spaces between the sand grains. The “cement” that sinters the sand grains together is called Calcite: calcium carbonate (CaCO 3 ). The “cement” that sinters the sand grains together is called Calcite: calcium carbonate (CaCO 3 ).

ELECTRON DIFFRACTION PATTERNS—THE BEAUTY OF CRYSTALLINE PERFECTION!