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Final_Review - NE 125 Introduction to Materials Science and...

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Unformatted text preview: NE 125: Introduction to Materials Science and Engineering Introduction Review Lecture Instructor: William K. O’Keefe, P.Eng. [email protected] “Being prepared and awaiting the unprepared is victory … Thus, the skilled Being can make themselves invincible” can - Sun Tzu (The Art of War) Final Exam: Breakdown Final Part I - Materials Selection and Failure Prevention Analysis Part Part II – Mechanical Properties (Ch. 6 ) Part III - Phase Behaviour and Microstructural Development Part IV – Structural Materials and Thermal Properties (Chapters 7,11,12,13, 14 and part of Ch 10) (Chapters Part V - Theory: Multiple Choice/ True and False Part VI - Atomic Bonding, Crystal Structure & Defects 25/125 = 20% 25/125 15/125 = 12% 15/125 = 12% 25/125 = 20% 25/125 20/125 = 16% 25/125 = 20% Chapter One: Introduction Chapter Materials classification by atomic bonding and constituents: metals, ceramics, polymers, semiconductors, composites, Advanced materials: biomaterials, nanostructured metals, Materials classification by morphology Materials amorphous, crystalline, semicrystalline, fractal, liquid crystal amorphous, Intro to ionic bonding, metallic bonding Intro Band Theory: insulators, conductors, semiconductors Band Optical transmission in solids; intrinsic versus extrinsic semiconductors; quantization of states, Pauli exclusion principle Chapter Two: Atomic Bonding Chapter Primary bonding (metallic, ionic, covalent bonding) Secondary bonding (Van der Waals, Hydrogen bonding) Secondary Partial ionic character Bonding Energy, coulombic potential energy, Madelung constant Madelung Lennard-Jones 6-12 potential Lennard-Jones NE 125: NE Introduction to Materials Science and Engineering Introduction In class sample problems Chapter 2 Shackelford 6th Ed 2-16 - Coulomb’s law and ionic bonding 2-27 - 1D crystal, Madelung constant A = 2ln2 2-28 - Madelung constant for 3D crystal 2-27 (1D crystal) kq 2 kq 2 kq 2 kq 2 E N = −2 +2 −2 +2 + ... a0 2a 0 3a 0 4a 0 E N = −2 kq 2 a0 kq 2 a0 1 1 1 1 1 − 2 + 3 − 4 + 5 + ... EN= −A NE 125: NE Introduction to Materials Science and Engineering Introduction First Quiz - Chapter 2 First 1) (10 marks) An Al2O3 whisker is a small single crystal used to reinforce metal-matrix composites. Given a cylindrical shape, calculate the number of aluminum atoms and the number of oxygen atoms in a whisker with a diameter of 1 µm and length 30 µm. The density of Al2O3 is 3.97 Mg/m3. NA = 6.022 x 1023 Atomic mass of oxygen is 15.999 and Al is 26.982 2) (20 marks) The net potential energy (EN) between two adjacent ions may be represented by the sum of the attractive and repulsive energies according to the following equation: EN= −k A k R +n r r Where r is the interatomic separation distance between the nuclei and kA and kR are empirically determined constants associated with attractive and repulsive forces respectively. Derive an expression which relates the bonding energy (E0) in terms of the parameters kA, kR and n. Chapter Three: Crystal Structure Chapter Single crystal vs polycrystalline materials Single Crystal structure and crystal habit Crystal 7 crystal systems, 14 Bravais lattices crystal Crystallographic points, planes, directions; Miller indices Crystallographic hcp, fcc, bcc, simple cubic structures hcp, Ceramic structures rock salt, CsCl, perovskite, etc. Ceramic Atomic packing factor, ionic packing factor, linear density, planar density Atomic metastability, polymorphism, allotropy, metastability, Determination of crystal structure (XRD and EDXRF) Determination Chapter Four: Crystal Defects Chapter Point defects (self interstitials, Schottky, Frenkel, vacancies) Point Linear defects (edge, screw and mixed dislocations; Burgers vector) Linear Relative dislocation energies Relative Solid solutions (Hume-Rothery rules); random and ordered solid solutions Solid Substitutional and interstitial solid solutions Substitutional Interfacial defects: surface coordinative unsaturation Interfacial isotropic and anisotropic materials isotropic grain boundaries, tilt boundary, twin boundary, ASTM grain size grain Microscopy (Optical, SEM, TEM, HRTEM, AFM) Microscopy Chapter Six: Mechanical Behaviour Chapter Stress versus Strain Stress Elastic Modulus, Shear Modulus, Engineering stress, engineering strain, true strain Elastic Ductility, % elongation, elastic recovery, Poisson’s ratio Ductility, Safe working stress, design factor, safety factor Safe Elastic deformation vs plastic deformation; fracture Elastic Slip in single crystals; Schmid’s law, critical resolved shear stress, slip in polycrystalline materials polycrystalline Slip systems (fcc, bcc, hcp) Slip Cold working, solid solution strengthening, strain hardening Cold Griffith crack model, modulus of rupture, flexural modulus Griffith Creep and stress relaxation Creep Chapter Eight: Failure prevention Chapter Fracture Mechanics: Ductile fracture, brittle fracture, fracture toughness, ductile to brittle transition, Charpy Impact test, Fatigue: S-N curve, mechanism Fatigue: Other failure modes: Other static fatigue, creep, stress corrosion cracking, galvanic corrosion, hydrogen embrittlement and attack, liquid metal embrittlement, intergranular corrosion, corrosion fatigue, complex failure modes, crevice corrosion, pitting, fretting (wear failure), Cavitation, thermal fatigue, graphitization, failure modes and effects analysis (FMEA) etc. (wear Failure Mitigation Case hardening, shot peening, polishing and surface treatments, geometry of mechanical design, transformation Case toughening, Nondestructive testing: ultrasonic testing, X-radiography, Beer-Lambert Law Nondestructive Chapter Seven: Thermal Behaviour Chapter Thermal Conductivity Thermal Heat Capacity Heat Thermal Shock Thermal Thermal Expansion Thermal Chapter Seven: Thermal Behaviour Chapter Thermal Conductivity Thermal Heat Capacity Heat Sensible heat, mean heat capacity, Einstein’s model of Cv(T) Sensible Thermal Shock Thermal Thermal Expansion Thermal Chapter Seven: Thermal Behaviour Chapter Thermal Conductivity Thermal Heat Capacity Heat Sensible heat, mean heat capacity, Einstein’s model of Cv(T) Sensible Thermal Shock Thermal Thermal Expansion Thermal Density calculations and effect of vacancy creation on density hole in plate, sphere through ring thermal expansion problems, heat flux through wall of furnace etc. of Chapter Nine: Phase Behaviour Chapter Material equilibrium: phase equilibrium Phase diagrams: binary, ternary, Gibbs Phase rule Gibbs Lever rule Lever Binary Phase diagrams Binary Binary eutectic, solid solutions, non-solid solutions, Ceramics, metal alloys; general phase diagrams Microstructural Development Invariant points and reactions: Proteutectic, proeutectoid, eutectic reaction, peritectic reaction, eutectoid reaction, Invariant eutectic/eutectoid structures, isomorphous alloys, nonequilibrium cooling, Microstructural development in eutectic, hypereutectic and hypoeutectic alloys Microstructural development in eutectoid, hypereutectoid and hypoeutectic alloys Microstructural Development of layered eutectic microstructure, homogeneous & heterogeneous nucleation, crystallization and Development growth growth Part II – Structural materials Part Ch 13 Polymers thermoplastics, thermoset, molecular weight distribution, polydispersity thermoplastics, Branched, linear and network Vulcanization and fraction of cross-linking sites Vulcanization thermal conductivity and branching, crystalline, semicrystalline, amorphous; lamellae and spherulites crystalline, Effect of structure on crystallinity, density, mechanical strength Effect Viscoelastic behaviour, glass transition temperature, Viscoelastic root mean square length, extended length, degree of polymerization root Polymer configurations and stereochemistry: tacticity, chain configuration, processing of thermoplastics: injection molding, induction of crystallinity from shear stress, polymer chain scission, haze, stretch blow molding, effect of crystallinity on oxygen permeability Mechanical properties: non-linear elastic deformation, mechanism, hysteresis, Mechanical Chapter 11: Metals Chapter Classification of metals ( Ferrous, non-ferrous, irons, steels, superalloys, etc) Classification Cast irons: malleable, ductile, white, gray, compacted graphite (CGI) Cast Steels: low, med high carbon steels; Stainless (Ferritic, austenitic, martensitic) Steels: Superalloys, nickel, magnesium, copper, bronze, brass, aluminum, titanium Superalloys, catalytic properties of transition metals; noble metals catalytic Microstructural development in carbon steel: pearlite Microstructural γ (.76 wt % C ) → α (0.022 wt % C ) + Fe3 C (6.70 wt % C ) Austenitizing, martensitic transformation (Ch 10), bainite, coarse pearlite, fine pearlite, sphereoidite, TTT diagrams, tempering sphereoidite, Strengthening of metals: annealing, precipitation hardening, effect of microstructure on mechanical properties effect Chapter 12: Ceramics Chapter Tetrahedra and octahedra as building blocks for complex ceramic structures Tetrahedra edge-sharing, face-sharing and corner-sharing octahedra and tetrahedra edge-sharing, Spinel, kaolinite, defect spinel structure, molybdenum trioxide, wurtzite, silicates, burgers vector in ceramics (alumina), non-stoichiometry, diffusion in crystals: (interstitial, Interstitialcy, vacancy diffusion, ringed and direct exchange exchange Viscoelastic behaviour (annealing pt., softening pt., working range, melting range) Viscoelastic ceramic phase diagrams classification of ceramics glasses: silicates vs. non-silicates, network formers, intermediates, network modifiers, Advanced ceramics: sol-gel, CVD, molecular sieves, MEMS, Chapter 14: Composites Chapter Particle reinforced composites Large particle vs dispersion strengthened materials Large Cermets, bound and occluded rubber in tires, Cermets, Concrete: Prestressed concrete, reinforced concrete, Portland cement, admixtures Concrete: Fiber reinforced composites (Fibers, whiskers and wires) Structural Composites: Laminates Sandwich panels Mechanisms of toughening, Crack deflection, fiber pullout, crack bridging Critical fiber length Isostrain versus isostress Load carried by fibers, load carried by matrix Property averaging Part III - Materials Selection Part Material science vs materials engineering Materials selection is an optimization problem: constraints, design criteria Ashby charts, performance indices, design guidelines Time dependent criterion: failure modes (fatigue, creep, corrosion, Time Ease of fabrication (welding machining, etc) , maintenance requirements, dissimilar materials, Engineering practice: engineering codes, statutory regulations, Impact of materials selection on the environment (re-cycle, waste, energy consumption for materials production and fabrication, Web based resources: MatWeb (materials properties database); O-rings chemical compatibility, T, P etc etc Case study I - Torsionally stressed cylinder Case study II – materials selection for valve spring in auto engine Case study III – mast for windsurfer board Case study IV – catastrophic failure of an o-ring Case study V – selection of an o-ring for a back pressure regulator; gasket selection for a CD reactor Part IV - Introduction to Nanomaterials Part Case study I Enhanced thermal insulation in a microelectronics circuit Nanowires as scattering centres for phonon propagation Phonons and Rayleigh scattering Boundary scattering Spectrally dependent phonon scattering (interfacial roughness) , phonon filters, Molecular junction: phonon polarization and phonon filtering effects Diamondoids, nanolaminates Carbon nanotubes: the strongest materials known, highest thermal conductivity No boundary scattering due to “seamless” structure Small size effect, quantum confinement effect, boundary effect Nanocomposites Heterogeneous catalysis: High specific surface area & degree of surface coordinative unsaturation Electronic effects, ensemble effects, bifunctional effects Nanoengineered catalyst for PEM hydrogen fuel cell ...
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