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Engineering 45 Materials of Engineering - Introduction Bruce Mayer, PE Licensed Electrical & Mechanical Engineer [email protected] Engineering-45: Materials of Engineering 1 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Course Goals Summarized Use the right material for the job • i.e.; Materials Application Understand the relation between PROPERTIES, STRUCTURE, and PROCESSING • i.e.; Materials Science & Engineering Recognize new design opportunities offered by materials selection • i.e.; Physical-Design Innovation Engineering-45: Materials of Engineering 2 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Class Q: Materials Engineering & Technology → What is it? Investigating the Structures & Properties of Materials and Correlating these with the Design or Engineering or Technology Objectives Engineering-45: Materials of Engineering 3 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt The Evolution of Materials Engineering-45: Materials of Engineering 4 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Materials Science & Engineering Materials are ENGINEERED Structures • Not Black Boxes Basic Material Structure Has Many Dimensions Structural Feature Atomic Bonding <10-10 Missing/Extra Atoms 10-10 Crystals (Ordered Atoms) 10-10 - 10-1 Second Phase Particles 10-8 - 10-4 Crystal Texturing Engineering-45: Materials of Engineering 5 Dimension (m) >10-6 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Structure, Processing, & Properties PROPERTIES depend on STRUCTURE • e.g.; The HARDNESS vs STRUCTURE of Steel (d) Hardness (BHN) 600 500 400 Ferrite + Cementite (a) G10380 + w/ Pearlite 200 100 0.01 0.1 4m 30m Tempered Martensite PROCESSING can change STRUCTURE 1 10 100 1000 Cooling Rate (C/s) Engineering-45: Materials of Engineering 6 UNtempered Martensite (b) 300 30m 30m (c) • e.g., STRUCTURE vs Cooling-Rate for Steel Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Classes of Materials From Chem1A Recall The Periodic Table of Elements Polymers Ceramics SemiConductors Metals Engineering-45: Materials of Engineering 7 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Metals May be Pure or Compounds (Alloys) • Along with Polymers The Most Common Everyday Material • Typically from the 1st Row of Transition Metals in Periodic Table (Fe, Cu, Ni, etc.) • Have LARGE Numbers of NonBound Electrons – Makes them Good Electrical & Thermal CONDUCTORS • Strong but Deformable (Ductile) Engineering-45: Materials of Engineering 8 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Ceramics Basic Composition is the MINERAL Form of a Metal • Very Few Metals Exist in PURE Form in Nature – Most That Do are Very Rare, e.g., Gold Ceramics are Compounds of Metals and • Oxygen → Oxides (most Ceramics) • Carbon → Carbides • Nitrogen → Nitrides Engineering-45: Materials of Engineering 9 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Ceramics cont. Some Typical Properties • HARD & BRITTLE • HIGHEST Temperature Resistance – Thoria (Thorium Oxide) Max Temp 3000 K • Llttle Temperature-SHOCK Resistance • Corrosion Resistant • Electrically Resistive (Insulative) • Difficult to Join – Do Not Weld Engineering-45: Materials of Engineering 10 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Polymers Many ChemUnits • MER A Basic Chemical Unit • POLY Many Chemical Compounds composed of, in VAST Majority, CARBON & HYDROGEN • Modified by the Presence of Other Elements – O, Si, F, Cl, N, many others Commonly Referred to as PLASTIC and/or (synthetic) RUBBER Engineering-45: Materials of Engineering 11 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Polymers cont. Some Typical Properties • Very LightWeight • Very Corrosion Resistant – Best of ANY Class of Material • Little, if any, Hi/Lo Temperature Resistance • Little Structural Strength • Very Deformable (ductile/flexible) • Lowest $-Cost:Volume Ratio for Any Class of Material Engineering-45: Materials of Engineering 12 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt SemiConductors May be made CONDUCTIVE or INSULATIVE (or Something in-between) by the Addition of Miniscule Amounts of IMPURITIES • Current Techniques Allow Precise Control over the AMOUNT and LOCATION of the Impurities Semiconductors are Very Important Electronic Device Materials Engineering-45: Materials of Engineering 13 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Semiconductors cont. Most SOLID STATE (no moving parts) Electronic Devices are Semiconductors Major applications for Semi Transistors • Voltage Amplifiers • On/Off switches Additional Advantage: Semiconductor Electronic Devices can be constructed at Extremely SMALL Scales SILICON is the Most Widely Used Engineering-45: Materials of Engineering 14 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Composites Materials that Consist of More than One Material Type • Goal is to Combine the Best Features of Multiple Materials Some Examples • FiberGlass = Glass (ceramic) + Polymer – Strength + Flexibilty • ReInforced Concrete = Steel + Concrete – Tension-Strength + Compression-Strength Engineering-45: Materials of Engineering 15 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt BioMaterials Defined as Those Materials Which Are compatible with Human Tissue • Classic Example = Stainless Steels used For Bone repair (Screws, Staples, Plates, Hip-Joints) At least a few of ALL other Classes of Materials are BioCompatible • Including Silicon Engineering-45: Materials of Engineering 16 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Smart Materials Smart Materials Materials That Can Sense Changes in the Environment and Respond with a Material Shape/Property Change • Example: "smart" materials that can be attached to, or embedded in, structural systems – enable the structure to sense disturbances, process the information and through commands to actuators, to accomplish some beneficial reaction Engineering-45: Materials of Engineering 17 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Smart Materials, cont. Potential Applications – Structural Systems • Machine Tools - Improve precision and increase productivity by controlling chatter • Flexible robotics - enable faster motion with greater accuracy • Photo-lithography - Enable the manufacture of smaller micro-electronic circuits by controlling vibration in the photo-lithography circuit printing process • Biomechanical & Biomedical - artificial muscles, drug delivery systems and other assistive technologies • Process Control - e. g., on/off shape control of solar reflectors or aerodynamic surfaces Engineering-45: Materials of Engineering 18 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt NanoTechnology Most Materials are Statistical Devices • i.e., Their Properties are the Average of a LARGE Number of Atoms or Molecules – A change in a Single NanoScale Particle does NOT affect Material Characteristics NanoScale Materials, on the Other hand, are built ONE NanoParticle at a time • Properties Can be PRECISELY Tailored Engineering-45: Materials of Engineering 19 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Materials Application Chain Processing Structure Properties Performance Selection Field Application SELECTION is the Critical Step for Physical-Design Engineers Engineering-45: Materials of Engineering 20 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Materials Selection 1. Pick APPLICATION → Determine Required PROPERTIES • Properties • • • • • • Mechanical Electrical Thermal Magnetic Optical Deteriorative • • • • Corrosion Wear Ageing UV exposure, etc. Engineering-45: Materials of Engineering 21 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Materials Selection cont. 2. PROPERTIES → Identify candidate Material(s) • Properties Follow • • COMPOSITION as Identified by CHEMICAL CONTENT STRUCTURE as Determined by Material-Formation Processing; e.g.: • • Amorphous vs PolyCrystalline vs FullyCrystalline Second (and perhaps Tertiary) Phases • • • • Type Quantity Size Distribution Engineering-45: Materials of Engineering 22 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Materials Selection cont.2 3. MATERIAL → Identify PROCESSING to Obtain Required Structure, and Hence Properties • Processing Changes STRUCTURE or SHAPE, but NOT Composition • e.g.: • • • • • • • Casting Sintering Thin Film Deposition (CVD, Sputtering, Evap, etc.) Forming or other Cold-Working Joining Annealing, Tempering, or other Heat Treatment Etc. Engineering-45: Materials of Engineering 23 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Material Properties Property Stimulus Result Mechanical load deformation, stress, strain Envt./Chemical chemicals, temp corrosion Terms “structural matls” modulus/stiffness, strength, toughness passivity, pollution (aqueous solution) “electronic matl.s” semiconductors, resistivity, dielectric magnets, hysteresis, moments Electrical electrical field conductivity Magnetic magnetic field magnetism Thermal heat conductivity heat capacity, thermal expansion Optical radiation (em, light) color, transparency index of refraction, reflectivity Material performance depends on material properties Engineering-45: Materials of Engineering 24 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Basic Material Properties Mechanical properties Thermal expansion General Density , kg/m3 Expense: Cost/kg Cm, $/kg o Mechanical Ductile materials Strength: Elastic limit y , MPa Fracture strength: Tensile strength ts , MPa Brittleness: Fracture toughness KIc , MPa·m1/2 Young’s modulus, E x Conduction: Thermal conductivity , W/m·K Tensile (fracture) Specific Heat (Capacity), cp or cv, J/kg·K ts Young’s modulus, E Electrical Conductor? Insulator? Conductivity σ, S/m Dielectric Capacity, F/m Strain Engineering-45: Materials of Engineering 25 Thermal conduction Thermal Brittle materials strength, Expansion coefficient, Temperature, T Expansion: Expansion coeff. , 1/K Strain Stress Young’s modulus E, GPa To T1 Area A Q joules/sec Heat flux, Q/A Stress Elastic limit,y Stiffness: Thermal strain Weight: Thermal conductivity, (T1 -T0)/x Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Mechanical Properties Example Stiff Strong Tough Light All OK ! Not stiff enough (need bigger E) modulus of elasticity Not strong enough (need bigger y ) yield strength Not tough enough (need bigger KIc) fracture toughness Too heavy (need lower ) density Engineering-45: Materials of Engineering 26 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Electrical Structure/Properties Electrical Resistivity of Copper Note: Resistivity, = 1/Conductivity • Resistivity → ρ (Ω-m) • Conductivity → σ (S/m) Adding “impurity” atoms to Cu increases resistivity Deforming Cu increases resistivity Engineering-45: Materials of Engineering 27 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Thermal Structure/Properties THERMAL Conductivity of Copper Adding “impurity” atoms to Cu (zinc to make a BRASS) Decreases Thermal conductivity Engineering-45: Materials of Engineering 28 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Magnetic Structure/Properties Magnetic Permeability vs. Composition for Iron Adding 3 atomic % Si makes Fe a Much BETTER magnetic recording medium Engineering-45: Materials of Engineering 29 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Optical Structure/Properties Aluminum Oxide Light Transmittance single crystal polycrystal: low porosity polycrystal: high porosity may be transparent, translucent, or opaque depending on the material structure Engineering-45: Materials of Engineering 30 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Deteriorative Structure/Properties SaltWater and STRESS can Cause Cracks in Metals Heat treatment: slows crack formation speed in salt-water exposed metal Engineering-45: Materials of Engineering 31 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt Materials Information for Design The goal of design: “To create products that perform their function effectively, safely, at acceptable cost” What do we need to know about materials to do this? More than just test data. Stat/Math analysis Data capture Selection of material and process Economic analysis and business case Mechanical Properties Bulk Modulus Compressive Strength Ductility Elastic Limit Endurance Limit Fracture Toughness Hardness Loss Coefficient Modulus of Rupture Poisson's Ratio Shear Modulus Tensile Strength Young's Modulus Test Test data Characterization Engineering-45: Materials of Engineering 32 4.1 55 0.06 40 24 2.3 100 0.00950 0.38 0.85 45 2.5 - 4.6 GPa 60 MPa 0.07 45 MPa 27 MPa 2.6 MPa.m1/2 140 MPa 0.026 55 MPa 0.42 0.95 GPa 48 MPa 2.8 GPa Design data $ Potential applications Successful applications Selection and implementation Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt © 2002, M.F. Ashby and D. Cebon Goals of Matls Engineering & Technology Select the Best Material for the Job Understand InterRelationships of • • • • If something goes wrong (“failure”) • Understand Why • Fix & Prevent processing structure properties performance Performance Processing Structure Properties Open new design opportunities with new materials Engineering-45: Materials of Engineering 33 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt WhiteBoard Work Problem Summary Here • List problem – Features – Constraints – Criteria – Goals Engineering-45: Materials of Engineering 34 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt IBM-Almaden Internship Target Audience • Projects and the program are designed for sophomores and juniors with majors in chemistry, physics, chemical engineering and related sciences Program Details Duration: 10 weeks, beginning June 7 or June 21, 2004. Stipend: Students $4500 for 10 weeks (not bad...). Eligibility: Undergraduate (pre-graduate school) standing, with preferably two years of chemistry. Requirements vary by project, but outstanding candidates at any level and technical major in science or engineering are encouraged to apply. Preference is given to chemistry, chemical engineering, and materials science majors. Participants must be citizens or permanent legal residents of the US. Engineering-45: Materials of Engineering 35 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt IBM-Almaden Internship The BAD News → A Pretty Nasty Set of Application Documents • Two App Forms • Two Letters of Req – I can Help • Personal Essay For the Forms see • http://www.almaden.ibm.com/st/info/studen topps/nsfstudent/NSFapplic.html Engineering-45: Materials of Engineering 36 Bruce Mayer, PE [email protected] • ENGR-45_Lec-01_Intro.ppt