| Unit I: In-service materials performance. |
Lesson 1. Fatigue
Definition and importance. Fracture surface characteristics. S-N curve. Fatigue crack propagation and service life prediction. Cumulative fatigue damage: Palmgren-Miner’s rule. Influence of the mean stress: Goodman and Gerber criteria. Factors that influence on fatigue.
Lesson 2. Fracture mechanics.
Griffith and Irwin theories. Linear elastic fracture mechanics. Stress distribution at the crack tip: plain stress and plain strain. Plain strain fracture toughness.
Lesson 3. Creep.
Influence of temperature on strength. The creep curve: creep rate, creep strain, temperature and stress. Creep tests for metals and plastics. Influence of stress and temperature. Prediction of long-time properties. Development of creep resistant alloys. Materials selection. Deformation mechanisms.
Lesson 4. Fundamentals of corrosion.
Economic and social importance. Electrochemical corrosion. Thermodynamic analysis. Electrode potential and Pourbaix diagrams. Kinetic analysis. Corrosion rate. Polarization phenomena. Passivation. Corrosion control strategies: design, change of material and/or exposure environment, protective layers, cathodic and anodic protection.
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| Unit II: Metal-casting and forming processes, heat treatments and joining processes. |
Lesson 5: Fundamentals of metal casting: especial casting methods.
Castability: fluidity, no cavities and resistance to hot cracking. Casting alloys. Directional solidification, casting for single-crystal components and metallic glasses. Squeeze casting. Semi-solid forming (rheocasting and thixocasting).
Lesson 6: Plastic forming of metals: cold working and hot forming.
Strain hardening. Characteristics of cold working. Annealing of a cold-worked piece. Hot forming: dynamic recovery and dynamic recrystallization. Characteristics of hot forming. Benefits of hot forming for cast structures.
Lesson 7. Heat treatments and thermomechanical treatments.
Quench and hardenability. Tempering. Martempering and austempering. Thermomechanical treatments: definition and types. Controlled rolling, ausforming, isoforming and marforming.
Lesson 8. Welding metallurgy.
Classification of welding processes according to AWS. Thermal cycle: influencing factors. Weld zone: epitaxial and competitive growth. Heat affected zone. Solid solution strengthened alloys. Work-hardened alloys. Precipitation hardened alloys. Transformation hardening alloys. Post-welding treatments. |
| Laboratory contents |
Laboratory 1. Fractography and fatigue testing.
Macroscopic and microscopic features of the fracture surfaces. Scanning Electron Microscope. Practical examples. Fatigue: general concepts. Fatigue testing: Wöhler curve. Factors that influence on fatigue. Examples.
Laboratory 2. Corrosion technology. Corrosion protection.
Electrochemical techniques for the corrosion assessment. Metallographic analysis. Assessment of protective layers. Thickness and adherence. Assessment of failure mechanisms.
Laboratory 3. Metallography I: forming techniques.
Cast structures: influence of cooling rate and alloying elements. Cold worked and hot formed structures.
Laboratory 4. Metallography II: heat-treated alloys.
Steels and Al alloys.
Laboratory 5. Hardenability. Jominy test.
Jominy curve. Objective and applications. Jominy test and results designation.
Laboratory 6. Liquid penetrating and magnetic particles testing.
Definition, objectives and applications. Testing methodology and report.
Laboratory 7. Radiography and ultrasounds (I)
Radiography: definitions, objectives and applications. Testing. Ultrasounds: through-transmission (transmitter-receiver) and pulse-echo modes. Ultrasonic inspection: calibration and thickness assessment.
Laboratory 8. Ultrasonic inspection (II)
Inspections of metallic pieces with a contact transducer. In-situ assessment of concrete structures. Sclerometer test: surface hardening and strength relationship. Ultrasonic inspections with the direct transmission mode. Ultrasonic pulse velocity in concrete: indirect mode. Ultrasonic pulse velocity and strength relationship.
Laboratory 9. Exposition of projects. Each student will participate in the exposition of his/her group and will answer the questions posed either by the lecturer and/or by students from other groups. |
