Chapter 1- Reading: Chapter 1 & 2. Class notes are in: WEB SITE HW # 1: due Thursday, September 4, 2008: Problems 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, ANNOUNCEMENTS

Chapter 1- CHEN 313: Materials Science and Engineering Course Objective... Introduce fundamental concepts in Materials S&T You will learn about: material structure how structure dictates properties how processing can change structure This course will help you to: use materials properly realize new design opportunities with materials a

Chapter 1- Lecturer: Dr Jorge Seminario Time: Tu&Th 2:20-3:35 pm Make up or additional classes: Tu or Th 7 PM (TBA) Location: CHEN 106 b LECTURES

Chapter 1- Teaching Assistants will grade your homework and exams Notice: goals of exams and HW are different One teaching assistant! Three graders!!! d TEACHING ASSISTANTS we have one now!!

Chapter 1- In my office: Wednesdays: 4:30-5:20 PM Thursdays: 3-4 PM In cyber-space: 24-7 Due to the large number of students virtual office hours will be preferred Responses to all students e OFFICE HOURS

Chapter 1- other books Required text: Fundamentals of Materials Science and Engineering: An Integrated Approach 3rd Edition W.D. Callister, Jr. and D. G. Rethwisch John Wiley and Sons, Inc. (2007). Both book and accompanying CD-ROM are useful. Other Materials: papers f COURSE MATERIAL

Chapter 1- exam # 1 15% exam #2 15% exam #3 15% final 40% g GRADING Homework, class participation: 15% projects, group work, quizes, etc.

Chapter 1- Materials are... engineered structures...not blackboxes! Structure...has many dimensions... Structural featureDimension (m) atomic bonding missing/extra atoms crystals (ordered atoms) second phase particles crystal texturing < > CHAPTER 1: MATERIALS SCIENCE & ENGINEERING

Chapter 1- Introduction Materials Science. Investigation of the relationships between the structures and properties of materials –How do the arrangement of a materials components (e.g. atoms, etc.) influence its properties (e.g. does it conduct electrons or not)? Materials Engineering. Designing the structure of a material so that it has desired properties.

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Chapter 1-

Introduction Another view of this course: –Macroscopic versus microscopic Engineers typically are interested in macroscopic properties (e.g. heat capacities, viscosity, fracture strength, etc.) Scientists often describe things in microscopic terms (e.g. bond strength, orbital theory, etc.) However, recent trends tend to mix both approaches: Engineers and Scientists both look at micro and macroscopic properties and try to understand the connection between them –In this class I am going to, whenever possible, show the interrelationship between microscopic and macroscopic properties

Chapter 1- Introduction Processing/Structure/Properties/Performance –They are interrelated! ProcessingStructureProperties Performance As engineers you are probably more tuned into processing and performance However, how processing influences the structure is critical Why? This will influence the material properties, which of course affect its performance!

Chapter 1- Introduction What do I mean by structure? –Structure is related to the arrangement of a material’s components This could be on any length scale Atomic, nano-, micro-, macro- –All of these length scales matter! Types of Carbon (just plain old carbon!) Diamond GraphiteC 60 - FullereneCarbon nanotubes

Chapter 1- Introduction Properties –How the material behaves in terms of the kind and magnitude of response to an imposed stimulus –What are the stimuli? Temperature Magnetic field Electric field –material properties are typically defined independent of material shape and size! –However… what about nanosize objects?

Chapter 1- Introduction Properties –For the purposes of this course we will group properties into six categories Mechanical Electrical Thermal Magnetic Optical Deteriorative

Chapter 1- Introduction PropertyExample (Physics)Example Properties MechanicalRate of material deformation to an applied load Elastic modulus ElectricalResponse of material to an applied electrical field Electrical conductivity ThermalMaterial expansion/contraction with change in temperature Heat capacity, thermal conductivity MagneticResponse of a material to an applied magnetic field Magnetic susceptibility OpticalResponse of material to electromagnetic radiation Refractive index DeteriorativeRate of decomposition of material (often in presence of acid, etc.) Corrosion rate

Chapter 1- Introduction Processing  Structure   Properties Same material – aluminum oxide. Depending on structure (which is influenced by processing) materials are transparent, translucent, opaque

Chapter 1- Introduction Classification of Materials –In materials science there have typically been three categories of materials Metals Ceramics Polymers –I will also use this convention; in addition there are several others that are variants (or combinations) of the three Composites Semiconductors Biomaterials

Material Categories Materials can be divided into five broad categories: –Ceramics –Polymers (plastics) –Composite materials –Metals and alloys –Liquids and gases

Material Categories Materials can be divided into five broad categories: –Ceramics –Polymers –Composite materials –Metals and alloys Provide high strength, stiffness, relatively easy to process –Liquids and gases Metal and alloys used for the construction of bridges and ships

Chapter 1- Introduction Metals –Defining characteristic of a metal High number of delocalized electrons –What does this mean? -- The electrons (outer valence e - ’s of the various atoms) are not bound to particular atoms –Impact delocalization has on properties? Metals are: »Good conductors of heat and electricity »Not transparent to visible light »Mechanically they are strong, yet deformable Examples – silver, gold, platinum, copper

Chapter 1- Introduction Ceramics –“Between” metallic and nonmetallic compounds Oxides, nitrides, and carbides These materials are typically insulators of heat and electricity More resistant to high temperature (e.g. high melting points) and harsh environments (e.g. pH) than metals Mechanically – ceramics are hard but brittle Examples: silica (glass), alumina, silicon nitride

Material Categories Materials can be divided into five broad categories: –Ceramics Fusion of powders (e.g, aluminum oxide) under high pressure and temperature. Properties: High temperature resistance, relatively high strength, brittle, hard, corrosion resistant –Polymers (plastics) –Composite materials –Metals and alloys –Liquids and gases

Chapter 1- Introduction Polymers –Plastics and rubber materials Macromolecules – generally formed from carbon, nitrogen, oxygen and hydrogen (chon systems or molecules) there are polymers that contain metals Usually have low densities Can be extremely flexible Not stable at high temperatures typically Examples: polyethylene, polystyrene, polyamide (Nylon®)

Material Categories Materials can be divided into five broad categories: –Ceramics –Polymers Include plastics and rubbers. Properties: Easy to fabricate, low weight, low cost, good insulators, low temperature resistance, weak, compliant and durable –Composite materials –Metals and alloys –Liquids and gases

Chapter 1- Introduction Composites –Exactly what it sounds like: a new material that consists of more than one component Fiberglass – glass fibers embedded in a polymeric matrix Idea – get desirable features of each material component Complicated though – does not always work out as well as you’d like

Material Categories Materials can be divided into five broad categories: –Ceramics –Polymers –Composite materials Combination of different materials (reinforcing component and binder). Properties: High strength to weight ratios, low weight, high stiffness, brittle –Metals and alloys –Liquids and gases Experimental aircraft: Entire body composed of composites

Chapter 1- Introduction Semiconductors –Materials with electrical properties intermediate of a metal (good conductor) and a ceramic (good insulator) –Silicon is the essential example – computer chips Key to use of semiconductors is the extremely precise control of dopant atoms that are used to manipulate the conducting properties

Chapter 1- Introduction Biomaterials –Use of the above materials in life science applications –Key point: the material must not lead to an adverse physiological reaction –Hip implants are the big success story here

Material Categories Materials can be divided into five broad categories: –Ceramics –Polymers –Composite materials –Metals and alloys –Liquids and gases Play a major role in heat transfer (e.g, radiator), hydraulic and pneumatic systems, lubrication

ex: hardness vs structure of steel Properties depend on structure Data obtained from Figs (a) and with 4wt%C composition, and from Fig and associated discussion, Callister 6e. Micrographs adapted from (a) Fig ; (b) Fig. 9.27;(c) Fig ; and (d) Fig , Callister 6e. ex: structure vs cooling rate of steel Processing can change structure Structure, Processing, & Properties Brinell Hardness Number (BHN) Brinell hardness test (BHN)

Chapter Pick ApplicationDetermine required Properties 2. Properties Identify candidate Material(s) 3. Material Identify required Processing Processing: changes structure and overall shape ex: casting, sintering, vapor deposition, doping forming, joining, annealing. Properties: mechanical, electrical, thermal, magnetic, optical, deteriorative. Material: structure, composition. 3 The Materials Selection Process

Material Selection Considerations Properties, Processing, Cost, Availability Importance of each one depends on application: –Military and Space applications pushing material properties and processing to their limits more important than cost

Chapter 1- Advances in materials (see pdf in website)

Materials Process Design and Control Laboratory MATERIALS DESIGN FRAMEWORK Machine learning schemes Microstructure Information library Accelerated Insertion of new materials Optimization of existing materials Tailored application specific material properties Virtual process simulations to evaluate alternate designs Computational process design simulator Virtual materials design framework

Materials Process Design and Control Laboratory DESIGNING MATERIALS WITH TAILORED PROPERTIES Micro problem driven by the velocity gradient L Macro problem driven by the macro-design variable β B n+1 Ω = Ω (r, t; L) ~ Polycrystal plasticity x = x(X, t; β ) L = L (X, t; β ) L = velocity gradient F n+1 B0B0 Reduced Order Modes Data mining techniques Multi-scale Computation Design variables (β) are macro design variables Processing sequence/parameters Design objectives are micro-scale averaged material/process properties Database

Chapter 1- Electrical Resistivity of Copper: Adding “impurity” atoms to Cu increases resistivity. Deforming Cu increases resistivity. 4 Adapted from Fig. 18.8, Callister 6e. (Fig adapted from: J.O. Linde, Ann Physik 5, 219 (1932); and C.A. Wert and R.M. Thomson, Physics of Solids, 2nd edition, McGraw-Hill Company, New York, 1970.) ELECTRICAL

Chapter 1- Space Shuttle Tiles: --Silica fiber insulation offers low heat conduction. Thermal Conductivity of Copper: --It decreases when you add zinc! 5 Fig. 19.0, Callister 6e. (Courtesy of Lockheed Missiles and Space Company, Inc.) Adapted from Fig. 19.4W, Callister 6e. (Courtesy of Lockheed Aerospace Ceramics Systems, Sunnyvale, CA) (Note: "W" denotes fig. is on CD-ROM.) Adapted from Fig. 19.4, Callister 6e. (Fig is adapted from Metals Handbook: Properties and Selection: Nonferrous alloys and Pure Metals, Vol. 2, 9th ed., H. Baker, (Managing Editor), American Society for Metals, 1979, p. 315.) THERMAL

Chapter 1- Magnetic Permeability vs. Composition: --Adding 3 atomic % Si makes Fe a better recording medium! Adapted from C.R. Barrett, W.D. Nix, and A.S. Tetelman, The Principles of Engineering Materials, Fig. 1-7(a), p. 9, 1973.Electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey. Fig , Callister 6e., (Fig is from J.U. Lemke, MRS Bulletin, Vol. XV, No. 3, p. 31, 1990.) Magnetic Storage: --Recording medium is magnetized by recording head. MAGNETIC

Chapter 1- Transmittance: --Aluminum oxide may be transparent, translucent, or opaque depending on the material structure. 7 Adapted from Fig. 1.2, Callister 6e. (Specimen preparation, P.A. Lessing; photo by J. Telford.) single crystal polycrystal: low porosity polycrystal: high porosity OPTICAL

Chapter 1- Stress & Saltwater... --causes cracks! Heat treatment: slows crack speed in salt water! 4m4m --material: 7150-T651 Al "alloy" (Zn,Cu,Mg,Zr) Adapted from Fig (b), R.W. Hertzberg, "Deformation and Fracture Mechanics of Engineering Materials" (4th ed.), p. 505, John Wiley and Sons, (Original source: Markus O. Speidel, Brown Boveri Co.) 8 Adapted from Fig. 17.0, Callister 6e. (Fig is from Marine Corrosion, Causes, and Prevention, John Wiley and Sons, Inc., 1975.) Adapted from Fig , Callister 6e. (Fig provided courtesy of G.H. Narayanan and A.G. Miller, Boeing Commercial Airplane Company.) DETERIORATIVE

Chapter 1- Use the right material for the job. Understand the relation between properties, structure, and processing. Recognize new design opportunities offered by materials selection. Course Goals: 9 SUMMARY