29773 - Metallurgy T

Learning outcomes

The course aims at discussing the basic criteria for microstructural and mechanical characterization of metals and alloys. The main learning objectives are: (i) how to select metallic materials to produce mechanical components working in a given service condition; (ii) how to identify the reasons for malfunctioning due to material-related features. Particular attention will be devoted to the presentation of the main microstructural, fractographic and mechanical characterization techniques for metals and alloys.

Course contents

Course introduction: presentation of course contents, teaching method and materials, as well as of assessment methods.

Mechanical testing and properties: hardness, tensile, fatigue, impact, creep, friction and wear. Basics on microstructural and fractographic analyses of metals.

Alloys and phase diagrams: Phases and structural constituents, binary phase diagram, phase and lever rules. Solidification and cooling of binary metal alloys.

Solidification microstructures and defects: casting technology basics. Nucleation and growth of pure metals and alloys. Influence of solidification microstructure and defects on mechanical properties. Solidification structures control methodologies.

Crystal structure and imperfections in the atomic arrangement: main crystal structures of metals and their effect on mechanical properties. Point defects and atom movements in materials (diffusion).

Dislocations and theory of plastic deformation: basics on the dislocations theory.

Strengthening mechanisms of metals: solid solution, grain refinement, precipitation, dispersion and strain hardening (plastic deformation technology basics). Influence of microstructure on electrical properties of metallic materials. Basics on dielectric properties of ceramics.

The Fe-C phase diagram: Phases and micro-constituents. Cooling and solidification of steels in equilibrium conditions. Equilibrium microstructures of carbon steels.

Designation and classification of steels.

Phase transformations in steels: Ferritic, perlitic, bainitic and martensitic transformation. TTT and CCT curves.

Heat treatments of steels: annealing, normalizing, quenching, tempering. Austempering.

Thermochemical diffusion treatments (carburizing, nitriding) for the enhancement of friction/wear and fatigue properties.

Aluminum alloys: properties and applications in energy generation systems. Main alloying elements, designation (casting alloys vs. wrought alloys), microstructures, heat treatments and mechanical properties.

Metallic materials in energy generation systems. Metals and alloys for high temperature applications (Ni and Co superalloys, refractory metals). Stainless steels (austenitic, ferritic, martensitic and duplex types). Designation, microstructure, properties and applications.

Selection criteria of metals as a function of the service conditions.

Readings/Bibliography

Course material (slides and notes in Italian). All the slides used by the teacher are available in the VIRTUALE repository, as password-protected pdf files (in Italian).

W.D. Callister “Fundamentals of Materials Science and Engineering”, J.Wiley and Sons (2001)

D.R. Askeland, P. Webster "The science and engineering of materials", Chapman & Hall (2007)

Teaching methods

Classroom lectures according to the timetable, unless otherwise arranged by the University. Interactive learning tests on the main concepts. Audiovisuals on the main (i) concepts and processes (ii) metallurgical lab methods.

Assessment methods

Examination in English can be arranged by previous contact with the teacher.

The final exam aims at assessing if the student learned how: (i) to select metallic materials and treatments for producing mechanical components that work in a given service condition; (ii) to identify the reasons for malfunctioning related to material features.

The exam consists of two parts:

1. Multiple choice test (30 questions, 4 options per question, 45 minutes);
2. Open oral questions (approx. 30 minutes). Scheduling of oral exams will be arranged after the conclusion of part 1 (multiple choice test).

Students will access the second part of the exam (open questions) only if a minimum of 18 correct answers in the first part (multiple choice test) are given. Answers to multiple choice questions will be evaluated as follows:

• +1 pt for each correct answer
• 0 pt for each missing or wrong answer

The final grade will be calculated as average of the grade for each part. The grade is expressed in x/30. The minimum score for passing the exam is assigned if satisfactory knowledge of all the subjects is assessed and there are no serious deficiencies.

Examples of questions as well as specific instruction on exam management are available in the teaching material available in the VIRTUALE repository.

Textbooks and electronic devices are not allowed during the examination.

Examinations schedule is available in advance on the University of Bologna web site AlmaEsami. Students willing to take the exam must join the student list on the web site AlmaEsami, carefully considering deadlines for student list opening and closing. Students are required to show their own ID before taking the exam.

Teaching tools

Classrooom lectures with both PC/slide projector and virtual or traditional blackboard. Interactive sessions for learning assessment (no grading) via apps like Wooclap or via VIRTUALE. Students are encouraged to attend Metallurgy classes to improve their final learning outcomes. The course attendance is not mandatory and it does affect the final examination score.

Services for students with special needs and students with specific learning disabilities may be arranged on request (https://www.unibo.it/en/services-and-opportunities/guidance-and-tutoring/disabled-and-dyslexic-students-service).

Office hours

See the website of Lavinia Tonelli