ME 435 Industrial Metallurgy - Past Course Outline (2024)

ME 435: Industrial Metallurgy Introduction to Industrial Metallurgy Sept. 10th, 2024 Important Points  Lecture slides, project assignments, and grades posted on LEARN  https://learn.uwaterloo.ca/login.asp  Accessibility issues (“AccessAbility”)  https://uwaterloo.ca/disability-service...

ME 435: Industrial Metallurgy Introduction to Industrial Metallurgy Sept. 10th, 2024 Important Points  Lecture slides, project assignments, and grades posted on LEARN  https://learn.uwaterloo.ca/login.asp  Accessibility issues (“AccessAbility”)  https://uwaterloo.ca/disability-services/  We’ll take breaks  Questions welcome  In person Quiz and Final exams  Project submission via Dropbox in LEARN  Conduct  Plagiarism  3 Course Outline  Instructor: Professor Yimin Wu Email: [email protected] Office: E7-3418 Extension: x40185  TA: Ms. Maryam Soleimani Email: [email protected] Office: E3-3173  Lectures: Tuesday, Thursday, 10:00-11:20pm EDT at MC 4064 Tutorials/TA office hour: Friday 1:00 pm – 2:00 pm EDT at E3-3173 Appointment with Professor Wu via email.  4 Grading ME 435 20% Mid term (Oct 22th) (Aluminium alloys, other non-ferrous alloys) 35% Lab project Progress report, Due Nov. 8th Final report, Due Nov.29th 45% Final exam (December 10th, to be determined) (All the course content)  5 Introduction  What is industrial metallurgy?  Metallurgy: the study of metals, intermetallic compounds, and alloys  Industrial Metallurgy: the practical application of metallurgy principles and manufacturing methods to produce useful parts with optimum properties  A key component to this is in understanding the material-processing- structure relationship Design of Manufacturing parts for Process applications Microstructure Alloy Chemistry Performance Material and properties Properties of the part  6 Course Objectives  To introduce the main types of metals and alloys used for engineering purposes and their properties  To understand how alloying elements and processing parameters affect microstructures and material properties for these alloys  To select the most appropriate metals or alloys for applications, given No the desired yes final part properties and yes the service conditions Yes No Yes No Yes Yes  yes yes No 7 Example Yes Yes Yes  Let’s say we wish to manufacture a chef’s knife with a good balance between properties and cost  What are our design criteria?  Inexpensive material, easy to process  Hard, able to hold a sharp edge with continued use  Resistant to rust/tarnishing (corrosion) either from use or from cleaning  8 Example  Let’s start by considering a few general types of metals/materials: Relatively High Corrosion Material Low Cost? Hardness? resistant? Ceramic / CerMet No Yes Yes Aluminum Alloy Yes No Yes Titanium Alloy No Yes Yes Steel Yes Yes No Stainless Steel Yes Yes Yes  9 Example  What kind of stainless steel should we use?  Stainless steels can be:  1) Ferritic (BCC)  2) Martensitic (BCT)  3) Austenitic (FCC)  4) Duplex (Ferrite + Austenite)  5) Precipitation-hardening (semi-austenitic, martensitic)  We see that the best combination of cost, hardness, and corrosion resistance for our particular application can be satisfied by martensitic stainless steel  10 Example  How do we get our martensitic stainless steel?  We will require a high Cr content ( >12 wt%)  Higher Cr content will give higher corrosion resistance  11 Example  To form hard martensite, the steel must be heated to form austenite, then quenched  Cr stabilizes ferrite, limiting the austenite phase field  To form austenite we must add an austenite stabilizer, such as C Fe-Cr Fe-Cr Fe-Cr + 0.05%C + 0.20%C Austenite  12 Example  The high Cr content gives the steel high hardenability  Only slow quenching method (i.e. oil, possibly air) necessary to form martensite in our small-sectioned knife Martensite Start  13 Example  As the as-quenched martensite can be brittle, we achieve optimum hardness and toughness by tempering  The graphs below show the variation of hardness with tempering temperature for 410 and 440C stainless steel  We can achieve higher hardness with the 440C stainless steel due to the additional C content 410 Stainless Steel 440C Stainless Steel 0.15% C, 12.5% Cr 1.05% C, 17% Cr  14 Example  Our kitchen knife is therefore designed as follows:  Material: 440C Stainless steel (1.05% C, 17% Cr)  Relatively low cost  Cr gives corrosion resistance  C gives high hardness  Processing:  Form to net shape (likely at elevated temperature) and austenitize  Can quench slowly to room temperature  Forms martensite due to high hardenability  Temper to optimum hardness/toughness combination  Finish with final grinding, sharpening Austenitize Temp Temper Time Form Finishing  15 Course Topics  Al and Al Alloys  Other Non-Ferrous Alloys (Mg, Cu, Ni, etc.)  Ferrous Alloys  Steel (plain carbon & alloy)  Stainless Steel  Tool Steels  Cast Irons  Surface Modification  16 Textbook (optional)  F.C. Campbell, Elements of Metallurgy and Engineering Alloys, ASM International, (2008).  Also available in DC Library (on reserve):  W.F. Smith, Structure and Properties of Engineering Alloys  K.G. Budinski, Engineering Materials, Properties and Selection  R.E. Reed-Hill, R. Abbaschian, Physical Metallurgy Principles  ASM Handbooks can also be found in the DC Library and online  An especially useful resource when working on your course project  17 Marking Scheme Course Item % of Final Mark Due Date Mid term 20 Tue. Oct. 22th Project 35 Tuesday. Nov. 29th Sat. Dec.10th (To be confirmed by the Final 45 University Register office)  18 Course Project  For the course project, groups are asked to identify the material and manufacturing methods used to produce parts for an automotive engine  Each group will select:  1 Ferrous Part  1 Non-Ferrous Part  1 Heat treated sample  Students will work in groups of 3  Sign-up in class using the signup sheet  19 Course Project  Objectives for the analysis are to identify for each part:  The alloy  Composition (main alloying elements and their amounts)  Compare with commercially-available alloys  Structure (phase or phases present in the part)  The processing method  Shaping of the part  Deformation processing (e.g. rolling), casting, machining, etc.  Heat treatments (if any)  What heat treatment parameters (e.g. temperatures) were used?  Surface Modifications (if any)  Coatings, case-hardening, etc.  Characteristics of the modified surface (e.g. coating thickness, composition)  Any additional properties or characteristics that make the material and manufacturing method used most appropriate  20 Course Project  Analysis techniques and equipment will include:  Metallography (polishing, etching, optical microscopy)  Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS)  Image Analysis  Heat Treatments (Furnaces, quenching)  Hardness Testing (Rockwell, Vickers)  Tensile Testing  Laboratory work will be demonstrated by the TA, at a time TBD  Project will be written in standard report format  Preliminary Report (SEM/EDS Findings)  Due Tuesday, Nov. 8th  Project due date: Tuesday, Nov. 29th (1 report per group)  21 Questions? Aluminum 2and Aluminum ex purealuminum alloys  no phase change 2 Outline a phase change  Introduction to Aluminum and its alloys  General characteristics & applications  Designations of Aluminum and its alloys  Materials designations & temper designations  Strengthening methods for Al Alloys  Solid solution strengthening  Precipitation Strengthening  Dispersion Strengthening  Strain hardening  3 General characteristics  Good corrosion and oxidation resistance  High electrical and thermal conductivities  High ductility and medium strength  Low density 2.7 g/cm3 (steel: 7.8 g/cm3)  4 Introduction  Second only to steel in importance/engineering applications  Price (US):  1850s: $500/lb  2006 $1.35/lb  2010 $1.00/lb  2016: $0.76/lb  5 General mechanical properties  6 Applications  Containers and packaging materials examples: pods, foils, beverage cans, cases  Structural materials in Architecture and Transportation examples: aircrafts, automobile vehicles, bicycles and children strollers  Electrical applications examples: Al wires, Copper clad Al wires  Radiators and cooking utensils Aluminum Alloys Cast Alloys  Manufactured by casting into a shape: Cast components.  Formulated for good casting properties; fluidity and flow  Heat treatable and non-heat treatable alloys Wrought Alloys:  Manufactured using a forming technique (after initial casting)  Includes sheets, foils, extrusions, wires, rods, etc.  Heat treatable and non-heat treatable alloys 7 Example: 8 Ingot Homogenization - Thermal Hot rolling Cold rolling casting preheating processing Scalping Intermediate final gauge annealing Solid solution single phase Dispersion second phase Precipitation second phase Annealing Thermal processing: Age hardening  9 Aluminum alloy designation Latticestructure Four-digit designation system by Al Association a  For wrought Al and Al alloys repulsion 1XXX, pure Al with over 99.00% 2XXX, Al-Cu 3XXX, Al-Mn 4XXX, Al-Si 5XXX, Al-Mg 6XXX, Al-Mg-Si 7XXX, Al-Zn-Mg 8XXX, other elements  10 Aluminum alloy designation  For cast Al and Al alloys:  The four – digit designation system incorporating a decimal point;  The number after the decimal are 0 (cast products ) or 1 (ingot) ;  A serial letter is preceding the numerical designation; A357.0 Cast product Higher purity level  11 Fabrication of Al alloys I 7 72underage Tretagé coarser particles lag particles incoherent interface large 3  12 Temper designations  F - As fabricated  O - Annealed  H - Work-hardened (HXX)  H1X - Cold worked only  H2X - Cold worked and partially annealed  H3X - Cold worked and stabilized  HX2 – ¼ hard  HX4 – ½ hard  HX6 – ¾ hard Residual hardening  HX8 - Hard  HX9 – Extra hard  W - Solution heat treated  T - Heat-treated (TX)  13 Heat-Treated temper designations T1 – Cooled from fabrication temperature and naturally aged T2 – Cooled from fabrication temperature, cold worked, and naturally aged T3 – Solution-treated, cold-worked, and naturally aged T4 – Solution-treated and naturally aged T5 – Cooled from fabrication temperature and artificially aged T6 – Solution-treated and artificially aged T7 – Solution-treated and stabilized by overaging T8 – Solution-treated, cold-worked, and artificially aged T9 – Solution-treated, artificially aged, and cold worked T10 – Cooled from fabrication temperature, cold worked, and artificially aged  14 Examples  What is a 6061-T6 alloy?  Answer: Al-Mg-Si alloy that is solution- treated and artificially aged  What is a 1100-O alloy?  Answer: Commercially pure (99%) aluminum that is annealed  What is a 3003-H18 alloy?  Answer: Al-Mn alloy that is strain-hardened to full hardness  15 Tx5x designation  Stress relieved  Tx51: stretch in tension  Tx52: compression  Tx54: combination of tension and compression  The function of stress relief:  Reduces warpage during machining  Improves the fatigue and stress-corrosion resistance  16 Strengthening methods for Al alloys  Solid solution hardening Solution heat treated (W)  Dispersion Strengthening (micron-scale particles)  Precipitation Strengthening (nano-scale particles) Solution heat treated and aged (T)  Strain hardening Various work hardening (H)  17 Solid solution strengthening  Source of strengthening: Strain field interferes with dislocation movement  The magnitude of strengthening depends on:  The atom size difference Interstitial or substitutional  Percentage of solutes  Problem caused  Natural aging  18 Dispersion Strengthening Copper – Aluminum Phase Diagram SS strengthening Dispersion strengthening by 2nd phase,  (slow cooling) (Askeland)  19 Heat treatments involved Askeland  20 Precipitation hardening  Aging conditions: temperature (T) and time.  21 Precipitation hardening  A typical precipitation sequence: GP Zones Ɵ" Ɵ' Ɵ 7xxx Precipitates (MgZn2) SSSS → GPI →GPII → η′ (metastable)→η (stable) V. Hansen et al., Materials Science and Technology 20 (2004) 185-193. 22  23 Effective precipitates  Small, hard, round, and a large amount  Coherent and in-coherent with matrix  Great matrix alignment  Great lattice strain  Example: Fully coherent precipitates in an Al-Cu alloy 24 (Clustering during natural aging) V. Fallah et al., Acta Materialia 61 (2013) 6372-6386 24  25 Strengthening Mechanisms  Interaction between precipitates and dislocations  Bowing  Shearing Hardening effect depends on: The volume fraction The interspacing The type 1 Volumetraction of particles overage coarse particles 2 particles If 1 Ty overage 3 Type interface Coherent vs in coherent  26 Example Questions Quiz  Draw a schematic hardness vs. time curve which shows “underaged”, “peak-aged” and “overaged” conditions of aging. hardness er me  Explain the drop in hardness for overaged conditions. Underage particle size not max Overage Bowing something with density  27 Two types of solid solution Octahedral interstice Tetrahedral interstice Interstitial atom lesser strain field Substitutional atom Cu alloy  28 Strain hardening IEEE refidual strain  Achieved by plastic deformation  Yield strength increases with the number of tensile testing  Dislocations density increase dramatically  Decreased grain size / 𝜎 = 𝑐𝐺𝑏𝜌 σ – Stress, C- Constant, G - Shear modulus  29 Strain Hardening  30 Cold working  Cold working increases strength (and reduces ductility)  Mechanism of strain hardening?  Grain structure also changes with cold working  Anisotropic behaviour EBSD electron backscatter defraction Before CW After CW 30  31 Annealing (O) Deformed structure:  Elongated grains Recovery  Non-isotropic properties Recrystallization  Decreased ductility Grain growth  32 Deep drawing A beverage can derives 70% of its strength as a result of strain hardening that occurs during its fabrication. https://www.youtube.com/watch?v =T9N1jy9lxd4 Callister  33 Question?  Which strengthening mechanism cannot be achieved in commercially-pure (1100) aluminum? (a) Solid solution hardening (b) Precipitation hardening (c) Strain hardening (d) Dispersion hardening  Solid Solution Dispersion Anneal a driving force energ ypapitan Egg semi coherent ggzgegzgyziz.mn stored in the man Grain growth atom diffusion Strain work largesingle crystal grain  34 Strain hardening and annealing  35 Background  Strain hardening or work hardening  Examples such as rolling, drawing, forging, extrusion  Increase the strength  Cold working  Hot working  Deformed structure  Deformed grains  Preferred orientation F.C.Campbell, Elements of Metallurgy and Engineering alloy, Materials Park, OH  36 Deformed structure  Dislocation density increases  Properties changed, anisotropic 0.1μm  Issues with strain hardening  Becomes harder to process ( high strength, low ductility)  Internal residual stress crack propagation and stress corrosion cracking F.C.Campbell, Elements of Metallurgy and Engineering alloy, Materials Park, OH L. Liao, Phd studies.  37 Texture & earing  Special orientation could cause earing RD Heat treatment W. F. Hosford, R. M. Caddell, Metal Forming, 2nd Ed., Prentice-Hall Inc. Edgewood Cliffs, HJ, 1993  38 Background  Annealing related to strain hardening  High temperature but below solutionizing T  Remove internal stress and preferred orientation, increase ductility, and form new grains  Recovery, recrystallization and grain growth form S.is 8ianjed infection I electrical thermal conductivity changes reverts DuctilityT ÉE F.C.Campbell, Elements of Metallurgy and Engineering alloy, Materials Park, OH strength dislocationdensityunchanged  39 Recrystallization  Definition  The replacement of the deformed cold-worked grains by new strain – free grains  Solid-solid transformation  Grain reforming and precipitation (for some materials) Energy  Driving force (ΔH) Ea  Stored energy from work hardening Deformed  Thermodynamically unstable ΔH Recrystallized  Thermal energy  Short-range diffusion Reaction coordinate  Activation energy (Ea) for diffusion  40 Recrystallized Temperature  Recrystallization takes place in a range  Recrystallization temperature (TR) at the temperature, recrystallization is finished in one hour  It’s proportional to the melting point Tin, 231.9 oC Low limit of TR for Tin is 0.6х (231.9+273) = 303  41 Nucleation Mechanisms  Nucleation at deformation heterogeneities:  Grain boundaries  Shear bands  Deformation bands  Large particles F.J. Humphreys, M. Hatherly, Recrystallization and related annealing phenomena, second edition  Nucleation Mechanisms 42 Previous grain boundaries (GB)  Strain induced GB migration (SIBM)  Tradition nucleation around GB The high angle boundaries are shown as black and low angle boundaries are as white S. P. Bellier, R. D. Doherty, Acta Metall. 25 (1977) 521-538a  43 Nucleation at shear bands  Shear bands are inclined by about 35-40o with respect to the rolling direction (RD) RD Microstructure of shear bands in Al-Mg Nucleation at the shear band after alloy annealing at 275 oC for 4.5 mins T. Koken, J. D. Embury, T. R. Ramachandran, T. Mails, Scripta Metall. 22 (1988) 99-103.  44 Nucleation at deformation bands Deformation bands in Al-1 % Mg Nucleation on a deformation band in alloy1 deformed pure Al2 1. F.J. Humphreys, M. Hatherly, Recrsystallization and related annealing phenomena, second edition 2. S. P. Bellier, R. D. Doherty, Acta Metall. 25 (1977) 521-538a  Nucleation at large particles 45 Schematic drawing of deformation zone around a large particle1  Localized strain concentrations at particle-matrix interfaces Nucleation around a large FeAl3 particle in 90% cold-rolled pure Al  Particle simulated nucleation during annealing at325oC2 mechanism (PSN) F.. J. Himphreys, M. Hatherly, “Recrystallization and related annealing phenomena,”Oxford: Elsevier Science:1995, pp.63 B.Bay, N. Hansen, Metall. Trans. A 10(1979)279-288. Pre-existed particles 46 Large particles (>1 µm) Particle simulated Deformation zones nucleation(PSN) Small particles Retard the movement of dislocations Zener drag effect  Zener drag force 47  A dispersion of precipitates retard the motion of a grain boundary For a random distribution of particles, the pinning force (pz) exerted on the boundary is given by: 3𝑓𝛾 𝑃 = 2𝑟 where, f and r are volume fraction and Boundary in Cu dragged by SiO2 particles radius of the particle. 𝛾 denotes the energy of grain boundaries Ashby and Palmer 1967  48 Grain growth  Normal grain growth  Uniform growth of grains  Continuous growth  Abnormal grain growth Abnormal grain growth in Al-1% Mg-1%Mn annealed at 600oC F.J. Humphreys, M. Hatherly, Recrsystallization and related annealing phenomena, second edition  49 Factors for recrystallization  Main factors affect recrystallization  Temperature of deformation  Degree of cold work  Purity of the metal  Original grain size  Temperature and time 10% 40% 80% F.C.Campbell, Elements of Metallurgy and Engineering alloy, Materials Park, OH  50 Investigation methods transmission electron microscopy  TEM  Hardness measurement  Electronic backscattered diffraction analysis (EBSD) typical recrystallization curve  Orientation map  Grain boundary map e  Texture characterization 7400m na Zdsino  51 EBSD application examples  Recrystallized microstructure of AA3xxx-AA 6xxx alloy system Clad side Core side 380oC-1h RD EBSD orientation map EBSD grain boundary map L. Liao, Phd studies.  52 EBSD working mechanism I View showing tilted sample and phosphor screen in SEM chamber Electron backscattering diffraction pattern from nickel  53 EBSD working mechanism II  54 Precipitation in deformed materials  High number density of dislocations accelerate precipitation during annealing  Free solutes in deformed microstructure tend to segregate along grain boundaries The effect of free solutes  Both the precipitates and free on grain boundary solutes could retard recrystallization F.J. Humphreys, M. Hatherly, Recrsystallization and related annealing phenomena, second edition  55 Precipitation & recrystallization  Precipitation can take place before, after or concurrent with recrystallization  Recrystallized grain structure changes with annealing temperature  56 Effect of annealing temperature on grain structure AA 3xxx Annealed at a higher temperature Annealed at a lower temperature S. Tangen, K. Sjølstad, T. Furu, E. Nes, Metall. Mater. Trans. A 41 (2010) 2970  57 AA3003-6xxx-1mm (80% thickness reduction) RD ND 300oC-24h 480oC-1h L. Liao, Phd studies.  58 Any questions?  1 Aluminum Alloys Part II 2 Casting Methods  Sand Casting  Most common method  Two-piece mould formed by packing sand around the desired shape  Produces rough surface finish  Permanent Mould Casting  Similar to sand casting however metal (cast iron) moulds are used  Moulds are preheated to ~200C to improve casting characteristics  Die Casting  Liquid metal is forced into a die under pressure under high velocity  Fast cooling rates are possible  Better suited for small parts 3  4 Sand casting Typical components are automobile engine blocks and ship propellers https://www.youtube.com/watch?v=gMs_MjYXXgQ Advantages:  Low cost  Cast complex shapes  Produce large component Disadvantages:  High labor cost per parts  Poor surface finish  Can not make thin sections http://www.doitpoms.ac.uk/tlplib/casting/sand_casting.php  5 Die casting http://www.doitpoms.ac.uk/tlplib/casting/die_ Advantages: casting.php  Low cost  Excellent surface finish, dimension accuracy  Fine grain structure  Produce thin sections Disadvantages:  Large capital investment  Only simple shapes can be cast  Can not be used for large castings http://www.doitpoms.ac.uk/tlplib/casting/die_casting.php  6 Selection of Casting Process 6 (ASM Handbook) Al Alloys Non-Heat Treatable Commercial Purity Alloys (1xxx) Composition:  Min 99% to 99.7% Al (with Si, Fe, and Cu); Strengthening Mechanism:  Strain-hardened; Properties:  Relatively soft and ductile with excellent workability and weldability and have good corrosion resistance Common Alloys:  1100, 1350 Applications:  Tubing, sheets, foil for capacitors, electrical conductors 8 1xxx Alloy Composition and Applications 9 Smith 1xxx Alloy Properties 10 Smith Aluminum-Manganese Alloys (3xxx) Composition:  Mn additions (up to 1.2%) to increase strength (+ 0.6% Fe, 0.2% Si) Properties:  Good strength, formability, and corrosion resistance Common Alloys:  3003, 3005, 3105, 3004 (has Mg addition to increase strength) Applications:  Cooking utensils, beverage cans, building products (siding, gutters) 11  12 Al_Mn Phase diagram Strengthening Mechanism: Strain-hardening; dispersion hardening; solid solution strengthening Dispersion hardening: Mn forms (Mn,Fe)Al6 and  (Al-Fe-Mn-Si) particles after cold working and annealing. Mn additions provide some solid-solution strengthening (low solubility limit) 3xxx Alloy Composition and Applications 13 3xxx Alloy Mechanical Properties (Campbell) 14 3xxx Alloy Micrograph 15 Smith Al 3004 Applications – Beverage Cans, 16 Pressure Vessels Aluminum-Silicon Alloys (4xxx) Composition:  Si additions (up to 13.5%) plus Cu, Mg, Ni, and Be  Generally non-heat treatable Properties:  High fluidity, Si reduces liquidus temperature Common Alloys:  4032, 4343 Applications:  Welding wire, brazing rods 17  18 Al-Si phase diagram  19 Cast of Al-Si alloys  Al-13% Si Eutectic point solidity liquid Problem: Coarse flakes of Si promote brittleness 12% hypereutectic eutectic point  20 Solution  Add a small amount of Na (0.01%)  Result: a fine, fibrous eutectic mixture of alpha and Si In this case hypoentectic is preferred https://www.southampton.ac.uk/~pasr1/al-si.htm#page5  21 Modified 356 Alloy Microstructure Effect of Modification on Mechanical Properties 22 of 4xxx Alloys Aluminum-Magnesium Alloys (5xxx) Composition:  1 – 5% Mg, low Fe, Si impurities, Mn (0.1 – 1%) & Cr (0.1 – 0.25%) added for grain refinement (provide some strength, as well) Strengthening Mechanism:  Solid-solution strengthening, no precipitation hardening despite decreasing Mg solubility with lower temperatures  High strain-hardening characteristics (H3 tempers)  Mg2Al3 particles can form at the grain boundaries with Mg content > 3.5% when slowly cooled from elevated temperatures making alloys susceptible to stress- corrosion cracking Properties:  Wide strength range, good forming, welding, and corrosion resistance Common Alloys:  5005, 5050, 5052, 5056, 5082, 5754 Applications:  Finishing and Decorative Alloys; Automotive inner panels Eutectic solid It solid 2 23 stress corssion cracking 22 Is EEnr.totmEdfcitzo.oa 3 internal stress  24 Al – Mg Phase Diagram  25 5xxx Alloy Composition Smith 25 5xxx Alloy Properties 26 (Campbell)  Al Alloys Age-Hardenable 1 Low impurity concentration Non heat treatable alloy 2 Phase diagram singlephase L if no impurities only 1phase  28 Applications of Heat Treatable Al Alloys Lower fuselage Al-Mg-Si (e.g. 6013, 6156) Wings Al-Zn-Mg (e.g. 7085) (upper wing) Airbus A380 Al-Li (e.g. 2099) (lower wing) Aluminum-Copper Alloys (2xxx) Composition:  4.5 to 6.3% Cu, 0.3 to 0.8% Mn Strengthening Mechanism:  Solid-solution strengthening  Age hardening (heat-treatable) 00  SSSS – GP1 – GP2 - ’ -  (CuAl2) Properties:  Good strength, weldability, resistance to stress-corrosion cracking, good high temperature properties Common Alloys:  2011, 2025, 2219 Applications:  Aircraft structural components 29 2xxx Al – Cu Alloy Composition 30 Smith  31 Heat treatment Precipitation sequence: nin.EE in d  32 Precipitation sequence Physical Metallurgy Principles, 3rd ed., by R.E. Reed-Hill and R. Abbaschian (Fig. 16.11) 32 2xxx Al – Cu Alloy Aging Profiles (Campbell) 33 Aluminum-Copper-Magnesium Alloys (2xxx) Composition:  Nominal 4% Cu, Mg, Mn, and Si additions Strengthening Mechanism:  Solid-solution strengthening  Age hardening (heat-treatable)  SSSS – GP zones - S’ - S (Al2CuMg) Properties:  Good strength, weldability, resistance to stress-corrosion cracking, good high temperature properties  Mg additions improve strength by improving age hardening Common Alloys:  2014, 2017, 2024, 2218 Applications:  Truck frames, aircraft engine components 34 2xxx Al – Cu – Mg Alloy Composition 35 (Smith) 2xxx Al – Cu (– Mg) Alloy Properties 36 (Campbell) Al-Mg-Si-(Cu) Alloys (AA6xxx) Composition:  Mg (0.6 – 1.2%) and Si (0.4 – 1.3%) additions  Cu added for enhancing strength  Mn, Cr added for grain refinement Strengthening Mechanism:  Solid-solution strengthening  Age hardening Properties:  Intermediate strength, fair formability, good corrosion resistance, good surface appearance Common Alloys:  6111, 6013, 6016, 6061, 6101, 6009, 6056, …… Applications:  General purpose, auto body sheets, heavy duty structures, architectural extrusions, electrical conductors 37  38 Age hardening  39 Precipitation Sequence  Cu-free: SSSS  Clusters  GP zones  ’’  ’   (Mg2Si)  Cu-containing alloys with appreciable Cu: SSSS  Clusters  GP zones  ’’+Q”  ’ +Q’   (Mg2Si) +Q Overaged at 300C unstable Peak-aged at 180C 2 AA6111 stable X. Wang, S. Esmaeili, D. J. Lloyd, “The Sequence of Precipitation in the Al-Mg-Si-Cu Alloy AA6111”, Metallurgical and Materials Transactions A, 37A (2006) 2691-2699.  L fmicfhjffsim.at's unstable gadgets these parties 40 Microstructural Evolution during Age Hardening g 400 350 Yield Strength (MPa) 300 250 200 150 100 50 AA6111 0 0.001 0.01 0.1 1 10 100 1000 Aging Time at 180 oC (h) X. Wang, S. Esmaeili, D. J. Lloyd, “The Sequence of Precipitation in the Al-Mg-Si-Cu Alloy AA6111”, Metallurgical and Materials Transactions A, 37A (2006) 2691-2699. 40 AP by D. Vaumousse, University of Oxford 6xxx Al – Mg – Si Alloy Composition 41 (Smith) 6xxx Al – Mg – Si Alloy Properties 42 (Campbell)  Aluminum-Zinc-Magnesium Alloys (7xxx) Composition:  4 – 8% Zn, 1 – 3% Mg  Cu additions (1 – 2%) increase strength Strengthening Mechanism:  Solid-solution strengthening  Age hardening (heat-treatable) an  SSSS – GP zones - ’ -  (MgZn2)  Duplex aging (120 hr @ 20C plus 48 hr @ 120C) produces highest density of GP zones  Single stage aging at higher temperatures produces coarse semi-coherent precipitates with wide precipitate free zones Properties:  Very high strength Examples of common alloys:  7085, 7075, 7050, 7030 Applications:  Structural load bearing applications: aircraft components, other transportation 43 7xxx Precipitation (MgZn2) SSSS → GPI →GPII → η′ (metastable)→η (stable) V. Hansen et al., Materials Science and Technology 20 (2004) 185-193. 44 7xxx Al – Zn Alloy Composition and Applications 45 (Smith) 7xxx Al – Zn Alloy Properties 46 (Campbell)  47 7xxx Temper Effects Aluminum-Lithium Alloys Composition:  ~2% Li additions  Cu and Mg added to provide strength Strengthening Mechanism:  Solid-solution strengthening  Age hardening (heat-treatable)  SSSS – ’(Al3Li) -  (AlLi)  Deformation before aging produces finer, denser precipitates (usually tensile) Properties:  Higher stiffness and lower density compared with 7075-T6  Good fatigue resistance in tension  Low ductility and fracture toughness  Expensive (3 – 5 times more) Common Alloys:  2090, 2091, 8090 Applications:  Aircraft and aerospace components, cryogenic applications 48 Al-Li Composition and Properties 49 (Smith)  50 CES 2011- EDU Pack  Fracture toughness vs tensile51 CES 2011- EDU Pack related to flaws toughness noflaws Energyfor flowto propagate Non-Ferrous Alloys (Mg, Cu, Ni) Chapter 27, 25& 29,30  2 Outline 1. Magnesium Alloys 2. Copper and its Alloys 3. Nickel and its Alloys 4. Super alloys Goal is to achieve a basic knowledge of some commercially-important non-ferrous alloy families  3 1. Magnesium Alloys  Density two-thirds that of aluminum (1.8 g/cm3) É  HCP structure  Poor ductility 12000 Lead alloys  Generally requires high forming temperature for wrought alloys Copper 10000  Good casting and machining properties Steels Cast Irons  Anisotropic behaviour due to HCP structure Density (kg/m^3) 8000 Ni based alloys  Not resistant to corrosion (used as sacrificial anode) 6000 Zn alloys  Oxidation and ignition issues Ti alloys 4000  Emerging applications  Transportation (currently cast parts in use in Al alloys limited cases) 2000 Mg alloys  Alloys for bio-resorbable implants  4 General Mechanical Properties Titanium alloys Age-hardening wrought Al-alloys Ni superalloys Wrought magnesium alloys Cast magnesium alloys 0.1 Cast iron, gray Zinc die-casting alloys Strength Carbon steel / Density Bronze (elastic limit) Stainless steel  Tensile Cast Al-alloys  Yield strength 0.01 Brass Specific Non age-hardening wrought Al-alloys Lead alloys Tungsten alloys Copper Tin 0.001 0.002 0.005 0.01 0.02 0.05 0.1 Young's modulus/ Density E Specific Tensile Stiffness   5 Corrosion Resistance Normal impurity elements: Fe, Ni and Cu The cause of galvanic corrosion  6 Alloying of Magnesium Al, Zn Improves strength and ductility Can also provide precipitation hardening Mn Removes Fe impurities to improve corrosion resistance Zr Powerful grain refiner Cannot be added with Al or Mn, as brittle intermetallics form Rare Earth Increases strength (solid solution and precipitation) (RE) Greatly increase ductility, and improve anisotropy of wrought products (texture) Ag Expensive, but greatly improves precipitation hardening Y Good for precipitation hardening, reduce flammability, and creep resistance Ca Oxidation, reduce flammability, grain size, creep resistance Fe, Ni, Cu Harmful impurities that reduce corrosion resistance  7 Alloying of Magnesium  8 Mg Alloy Designations ex AQ21A 76 2nti Al Inti Ag  9 Mg Casting Alloys  Mg-Al-Zn  Most common casting alloys  Solid solution strengthening 1 single phase  Can be precipitation hardened (Moderate) 2 phases 0 0 0 00  10 Mg-Al-Zn rwti.tn  Higher-purity grade AZ91E has good corrosion resistance characteristics AtIn 23rdpart  Corrosion rate in salt fog 100x less than AZ91C  Comparable corrosion to some Al casting alloys  11 Mg Casting Alloys  Mg-Zn-Zr (ZK)  Higher strength but lower castability than AZ series  Mg-RE-Zn-Zr (ZE)  Decent castability, improved creep resistance  Used up to 150 oC  Mg-Thorium (HK, HZ)  Increase creep resistance, used up to 175 oC.  Radioactive  Mg-Ag (QE)  Can be precipitation hardened for good strength (i.e. QE22)  Used up to 205 oC.  Mg-Y (WE)  Good strength at room temperature and elevated temperatures  Used up to 300 oC  12 Mg Casting Alloy Compositions  13 Mg Casting Alloy Properties  14 Mg Wrought Alloys  The limited formability of magnesium greatly limits the use of wrought alloys, especially compared to Al < 𝑎 > slip < 𝑐 + 𝑎 > slip Most slip is basal Slip with a component Mg alloys will readily form (0001)- normal to the basal twins to accommodate plane is not easily plastic strain activated  g 15 Mg Wrought Alloys  Mg-Al-Zn again the most common alloy system  AZ31B the most common wrought Mg alloy  Mg-Zn-Zr alloys also provide good strength and toughness  i.e. ZK60A  Alloying with RE elements, even at low levels, can greatly increase alloy ductility and texture  Currently a very active area of research for Mg alloy development  16 Effects of RE Addition to Wrought Mg Addition of 0.2 wt% Ce  17 Mg Wrought Alloy Compositions  18 Wrought Mg Alloys 1 cm  1 mm AZ31 Mg sheet rolled to 15% reduction at room temperature:  Twin Roll Casting:  19 DC & Twin Roll Casting  https://www.youtube.com/watch?v=HvouM eeJFzk  20 Heat treatment  Annealing at 290-455oC  Stress relieving at 150-450oC to reduce residual stress  Prevent stress corrosion  Improve allowance of precision  Reduce warpage and distortion  Solution heat treatment at 390-525oC  21 Biodegradable Mg alloys  Magnesium alloys as a dissolvable biomaterial for medical devices.  Problems  Corrosion resistance  Elastic modulus http://www.meddeviceonline.com/doc/dissolvable-metal- implants-disappear-once-patient-heals-0001  22 3. Copper and its Alloys  Probably the first metal used by human beings.  Copper ranks third behind iron and aluminum in commercial applications.  Relatively expensive (6 times the cost of mild steel)  Most copper comes from copper sulfide deposits that go through refining processes to achieve commercially pure copper.  Pure Cu has FCC structure  Alloyed mainly with zinc (brasses), tin (bronzes) and Ni (cupronickles, nickel silvers)  23 General Properties  Density: 8.93 g/cm3  Excellent formability and castability  Good strength when alloyed  High thermal conductivity  Good corrosion resistance  Germicidal / Antimicrobial  Very high electrical conductivity in pure form  24 Electrical Conductivity Effect of alloying Cu on conductivity  25 General Applications  Pure Cu used for wires and cables, electrical contacts, and other electrical conductor applications.  Cu alloys used for applications requiring heat conduction (e.g. automobile radiators, heat exchangers, home heating systems).  Cu and its alloys are used for many applications requiring corrosion resistance in water and other aqueous solutions (e.g. pipes, valves, fittings and coinage).  26 Classification of Cu and Cu Alloys Coppers (>99% Cu)  Wrought alloys High-copper alloys (>96% Cu) Brasses (Cu-Zn-…) Bronzes (Cu-Sn-….)  Cast alloys Copper nickels (Cu-Ni-Fe) Nickel silvers (Cu-Ni-Zn-…) Others  27 Copper Alloy Classification C1xx Coppers and high-copper alloys Wrought alloys C2xx Cu-Zn alloys (brasses) C3xx Cu-Zn-Pb alloys (leaded brasses) C4xx Cu-Zn-Sn alloys (tin brasses) C5xx Cu-Sn alloys (phosphor bronzes) C6xx Cu-Al alloys (aluminum bronzes), Cu-Si alloys (silicon bronzes), and misc. Cu-Zn alloys C7xx Cu-Ni and Cu-Ni-Zn alloys (nickel silvers) C8xx Coppers, high-copper alloys, the brasses of various alloys Cast types, Mn-Bronze alloys, Cu-Zn-Si alloys C9xx Cu-Sn, Cu-Sn-Pb, Cu-Sn-Ni, Cu-Al-Fe, Cu-Ni-Fe, and Cu-Ni-Zn alloys Coppers: min Cu content of 99.3% High-copper alloys: 36 wt% Zn  phase is brittle and should be avoided.  34 Cu – Zn Brass Microstructure  The microstructure of annealed cartridge brass contains extensive annealing twins (right)  Care must be taken to not overheat the alloys, as it can lead to excessive grain growth, and an “orange peel” surface texture (below)  35 Corrosion of Brasses  Stress Corrosion Cracking  Brass with over 15% Zn susceptible if in contact with trace amounts of ammonia with oxygen and moisture  Called season cracking  Eliminated with stress relief anneal  Dezincification  Preferential corrosion of Zn (>15%) which leaves porous Cu surface  0.04% arsenic (or P, Sn) added to prevent it  36 Brass – SCC  37 Brass – Dezincification  38 Copper–Tin Alloys (Bronzes): C5xxxx  Properly called “tin bronzes”  Frequently referred to as phosphor bronze due to trace amounts of phosphorus for deoxidation  Possess high strength, wear resistance, and sea-water corrosion resistance  Wrought alloys, containing less than 10% Sn, have good cold-workability  Above 10% Sn, alloys unworkable  Casting alloys contain up to 20% Sn, used for high strength bearings and gear blanks  E s.isYIBisaidzsEsts EEEsiidas rcsolid3 39 Copper – Aluminum Alloys (Al Bronzes): C6xxxx  Very hard, high tensile strength, tough and wear resistant alloys with good corrosion resistance  Usually contain 5 – 8% Al  Eutectoid reaction at 11.8% Al @ 565C     + 2 (aluminum bronze pearlite)  Like steels, can form ’ tetragonal Letested martensite by quenching which can then BCT be tempered structure  Slow cooling produces low strength, brittle 2 phase, which should be avoided  Al bronzes with 10% Al, 5% Fe, and 5% Ni are strong, tough, and have good corrosion resistance  These alloys used for high strength bearings, springs, and die applications  40 Copper – Silicon Alloys (Si Bronzes): C6xxxx  Used as lower-cost alternatives to Tin bronzes  Trade names: Everdur or Herculoy  Contain 1 – 4% Si  Severe cold working can produce very high strengths  Mn alloying additions improve high-temperature strength and wear resistance  Used in chemical processing plants due to high strength and good corrosion resistance  41 Copper – Beryllium Alloys  “Red” Alloys: 0.2 – 0.7 wt% Be, 1.4 – 2.7 wt% Ni/Co  “Gold” Alloys: 1.6 – 2.0 wt% Be, 0.25 wt% Co  May be age hardened  GP  ’   (CuBe)  Cold working before age hardening increases strength by increasing number of GP zones  Tensile strengths >1400 MPa possible (highest strength for commercial Cu alloys)  Gold alloys higher strength than red alloys  Co, Ni form dispersoids that restrict grain growth during solutionizing  Used extensively for non-sparking tools in potentially explosive environments (e.g. mines, chemical plants)  Also used in high strength applications like springs, electrical contacts, and dies  Alloys can be costly  42 Cu – Be Phase Diagram  43 Copper – Nickel Alloys (Cupronickels): C7xxxx  Ni forms complete solid solubility system with Cu  Continuous change in properties with composition  Ni increases the strength, oxidation, and corrosion resistance of copper  Cu is strengthened by solid solution strengthening  Used for sea water piping, condenser tubes, and heat exchangers  Ni decreases electrical conductivity of Cu  60% Cu, 40% Ni has lower conductivity but changes very little with increasing temperature  Useful for accurate electrical instruments  44 Cu – Ni Phase Diagram T.pitaionstengthen.mg dentition  g 45 Cu – Ni Alloy Properties  46 Cu – Ni Alloys  Cu-25%Ni alloy is also used as cladding of coins over copper cores Cu-Ni Clad Cu Core Cu-Ni Clad  47 Copper–Nickel–Zinc Alloys (Nickel Silvers): C7xxxx  Do not contain silver  Named for their silver colour  Single-phase alloys: 60-63% Cu, 7-30% Ni, Zn balance  Excellent cold working properties  Two-phase alloys: (approx.) 45% Cu, 45% Ni, 10% Zn  Inferior cold working properties but can be easily hot-worked  Have medium to high strength, excellent corrosion resistance  Need to stress-relieve to prevent stress corrosion cracking  Frequently used for as a base for silver plated pieces where it will be hard to see when the plating has worn away  (e.g. tableware, jewellery, name plates)  48 3. Nickel & Nickel Alloys  Discovered in 1750, but had limited use until the 20th century  Main use is as an alloying element in stainless steels  Alloying element in other alloys  E.g. alloy steels, Cu alloys  Also used for Ni electroplating  Occurs in nature in the form of sulfides or oxides  The Canadian ore is primarily a sulfide with a nickel content of less than 3%  49 General Characteristics of Nickel  Nickel and most high-nickel alloys have the same appearance as steels  Ferromagnetic up to 360°C  Density: 8.9 g/cm3  Melting point of pure Ni: 1455°C  Relatively good electrical conductivity  used for high temperature electrical conductors  FCC structure: generally very good ductility and toughness  50 Nickel Alloys  Typical solid solution strengthening elements:  Co, Fe, Cr, Mo, W, V, Ti, Al, Nb, Ta  W, Nb, Ta, Mo particularly effective at elevated temperatures  Ni does not form carbides itself, but carbides can harden Ni alloys by forming from C and other transition metals  E.g. Cr7C3  Ni alloys can be significantly strengthened by precipitation hardening  Formation of 𝛾’ phase: Ni3(Al,Ti)  𝛾’ phase also has FCC structure with small lattice mismatch  Leads to excellent thermal stability  Ni alloys also strengthen very well from cold-working  Generally hardens more with cold work than steels  51 Nickel Alloys  Commercially-pure (CP) and Low-Alloy Nickels  Highly corrosion resistant (both oxidative and reducing environments)  Additions of C may embrittle the alloy by precipitation of inter- granular graphite  S can cause embrittlement at high temperatures  Mn added to protect from sulfidation  Small Al and Ti additions can improve strength by precipitation of 𝛾’ phase  E.g. Duranickel 301 (Ni-4.5Al-0.5Ti)  Ni-Cu Alloys  High strength and toughness with excellent corrosion properties  Used in chemical processing and pollution control equipment  Good properties in seawater, especially in high velocities where cavitation erosion may be a factor  Used as propellers and propeller shafts  52 Nickel Alloys  Ni-Mo & Ni-Si Alloys  Improved resistance to reducing acids, particularly HCl  Weakened resistance to oxidizing environments  Ni-Cr-Fe Alloys  Developed for high-temperature oxidizing environments  Cr content allows for protective surface film of Cr2O3  Used for heat exchangers, carburizing equipment, and nuclear steam generator tubing  Ni-Cr-Mo Alloys  Most corrosion resistant of all Ni alloys  Combination of Cr and Mo improves resistance to oxidizing and reducing environments, respectively  Used in very aggressive service environments  53 Ni Composition and Properties  54 Ni-Fe Alloys  Fe has a dramatic effect on the thermal expansion coefficient of Ni  Ni-Fe alloys have the lowest coefficients of thermal expansion among major alloys  E.g. Invar (63-Fe-36Ni)  55 Other Nickel Alloys  Electrical resistance alloys  Used for electrical control systems and high-temperature heating elements  Magnetic alloys  Can be tailored to have both hard and soft magnetic properties  Shape memory alloys  Can be deformed plastically, and will revert to their previous shape when heated  Origin is deformation by twinning of thermoelastic martensite, which is reversed when the material is heated to form austenite  The temperature of this transition can be tailored by alloying element additions  Most common alloy: Nitinol (50Ni-50Ti)  56 Shape memory alloys  https://www.youtube.com/watch?v=- K57cbOhA5g  https://www.youtube.com/watch?v=s62PL 5vmfNw  https://www.youtube.com/watch?v=1rrPv5 AlVXg  57 4. Superalloys  High-performance alloys that exhibit excellent strength, creep resistance, and corrosion/oxidation resistance, even at high temperatures  Most commonly used for demanding applications:  Aerospace  Gas turbines  Nuclear reactors  Predominant application is in jet engines  58 Jet Engine Component Materials  59 Superalloys  Superalloys are based on the following systems:  Ni, Fe-Ni, Co  All three have an FCC structure  For Co, Fe FCC is stabilized for all temperatures by alloying elements  Some superalloys are so highly alloyed that they can only be produced by powder metallurgy or mechanical alloying  Main strengthening mechanisms:  Solid solution strengthening  Precipitation hardening (Ni and Fe-Ni alloys)  𝛾’ phase: Ni3(Al,Ti)  𝛾’′ phase: Ni3Nb  Grain boundary carbides/borides  Also retard creep by grain boundary sliding  Not as important for single-crystal parts  Protective oxide surface layer formed by:  Cr (Cr2O3)  Al (Al2O3)  60 Superalloy Microstructure (Ni-based) Original image: x6000 magnification  61 Superalloys  Ni Based  Most common and complex, used for most demanding applications  Lower temperature alloys are strengthened mainly by solid solution elements  E.g. Hasteloy series  Highest strength, high-temperature alloys are precipitation hardened  E.g. Inconel 718, Waspaloy  Inconel 718 most common superalloy  Can also be strengthened by mechanical alloying with oxide particle dispersion (i.e. Y2O3)  E.g. MA-series  62 Superalloys  Fe-Ni Based  Can be solid solution strengthened or precipitation hardened  Also come in varieties with very low thermal expansion coefficients  E.g. Inconel 903, 909  63 Superalloys  64 Turbine blades  65 Turbine Blade Grain Structure  66 Superalloy Coatings  Design of superalloys for increased strength can compromise their oxidation resistance  Can improve the high temperature oxidation resistance with appropriate coatings  At high temperatures, Al2O3 is the most effective oxide layer  Many protective coatings involve Al deposition (as aluminides, e.g. NiAl) to increase surface Al content The result of 2500 h low altitude sea flight service on an uncoated and NiAl coated blade turbine blade. The Iron-Carbon System Chapter 10 Iron-Carbon System  Fe – C Phase Diagram  Solid Phases  3 – Phase Reactions  Eutectoid, Hypoeutectoid, Hypereutectoid Plain Carbon Steels  Isothermal Transformations  Pearlite  Martensite  Bainite  Eutectoid Steel  Hypoeutectoid Steels  Hypereutectoid Steels 2 Iron – Carbon Phase Diagram Fe3C: Orthorhombic crystal structure 3 (Campbell)  4 Ferrous Alloys  Fe the prime metal; carbon alloying element; other alloying elements also used.  General classifications based on C content:  Irons, i.e. commercially pure Fe (wt%C < 0.008)  Steels (0.008 < wt%C < 2, usually 0.01