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MATERIALS SCIENCE AND TECHNOLOGY

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Versione italiana
Academic year
2021/2022
Teacher
ANDREA BALBO
Credits
9
Didactic period
Secondo Semestre
SSD
ING-IND/22

Training objectives

The course provides the fundamental knowledge for the analysis of the mechanical behavior of materials, through the correlation of their macroscopic properties to the microscopic ones. Some mechanical tests are also described and the properties derived are used to solve simple problems, concerning the material selection for specific applications.
In particular, the main student outcomes provided at the end of the course will be:
acquisition of a good command of technical language and terminology useful to express themselves and to understand technical texts and tables related to the studied discipline
basic knowledge of the mechanical behavior of materials in relation to their composition, microstructure and crystalline or glassy nature
ability to forecast possible variation of mechanical performances when field conditions change
for ceramic materials, comprehension of the production technology-microstructure-properties interconnections
possibility to address the choice of materials for specific applications
capability of proposals aiming at increasing component service life.

Prerequisites

The course requires knowledge of the content of the course “Fundamentals of Chemistry and Materials”, in particular as regard as the nature and properties of atomic bonds, the solid-state structure, phase diagrams and elementary thermodynamic concepts. Moreover, basic concepts of Mathematics and Physics are required, in particular those related to the differential and integral calculus and the notions of force, work, energy, pressure, density, etc.

Course programme

The course includes 90 hours of teaching consisting in lessons and exercises. In particular, it consists in 72 hours of theoretical lessons and 18 hours of exercises, cases of material choice and visits to companies / research laboratories working in the field of science / technology / production of advanced materials.

Elastic properties. Dependence of the elastic modulus on the strength of atomic bonds. Anelastic properties. Processes leading to anelastic behaviour in different materials. Specific damping capacity and loss coefficient (4h)
Structural imperfections in crystals. Vacancies. Dislocations. Stacking faults. Grain boundaries. Strain hardening mechanisms (8h)
Plasticity in single crystals. Slip systems. Schmid law. Plasticity in polycrystals. Hall-Petch relationship (3h)
Temperature and strain-rate effects on tensile behaviour. Superplasticity. Fractography elements: dimple rupture and cleavage (4h)
Griffith crack theory. Elements of fracture mechanics. Stress-intensity factor. Strain energy release rate. R-curve. Strategies to increase toughness in materials (8h)
Creep behavior. High-temperature deformation mechanisms. Characteristics of materials for elevated temperature use (6h)
Mechanical tests: tensile test, compression test, torsion test, impact test, fracture toughness test, creep test (9h)
Introduction to advanced ceramic materials. Definitions. mechanical properties of advanced ceramics. Weibull statistics. Static fatigue (6h)
Nature of the ceramic powder. Particle size distribution and fundamental physical properties. Thermal analysis (3h)
Slip and plastic mix formulations. Electric double-layer. Processing additives (4h)
Powder granulation. Forming techniques: dry pressing, isostatic pressing, extrusion, injection molding, slip casting and tape casting (3h)
Drying. Organics removal. Solid-state sintering, liquid-phase sintering. Hot pressing. Effect of sintering on pore structures and grain growth (6h)
Production and engineering properties of different oxide and non-oxide ceramics. Stress-induced transformation toughening (5h)
Nature and structure of glass. Conditions for glass formation. Glass-transition temperature. The role of different oxides on the glass structure. Glass composition-property relationships: viscosity, thermal expansion coefficient, density, stiffness. Thermal and chemical tempering. Annealing (3h)
Materials selection in mechanical design. Materials selection charts. Performance indices (8h)
Numerical exercises and guided tour to research laboratories / industrial facilities (10h)

Didactic methods

The course consists of a series of frontal lectures with visual support (slideshow) and class discussion. Student interest is stimulated by illustrating several case studies of material application in relation to their properties. Numerical exercises are performed to become familiar with the studied properties and the measure units and to recognize their application in engineering practice. Depending on the availability of research centers / companies in the sector, there will be a guided tour at industrial laboratories / facilities operating in the discipline studied.

Learning assessment procedures

The achievement of the learning goals is assessed by an oral examination, which includes a series of theoretical questions and the solution of a simple numerical exercise related to mechanical properties. The final grade is formulated on the basis of:
- Competence achieved in the studied discipline (50%)
- Accuracy in numerical analysis (20%)
- Correct use of technical language and clarity of exposition (30%)

Reference texts

- Teacher's notes

For further information on specific topics:

- R. W. Hertzberg, Deformation and fracture mechanics of engineering materials, John Wiley & Sons, Singapore, 1989.
- G.E. Dieter, Mechanical Metallurgy, McGraw-Hill Book Company, Singapore, 1988.
- I. Amato, L. Montanaro, Lezioni dal corso di scienza e tecnologia dei materiali ceramici, Ed. Libreria Cortina, Torino, 1997.
- J. S. Reed, Principles of ceramics processing, J. Wiley & Sons, 1995.
- M.F. Ashby, Materials selection in mechanical design, Pergamon Press, Singapore, 1992.