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 for the production of mechanical components working in a given service condition (ii) how to identify the reasons for malfunctioning related to material 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: tensile, hardness, fatigue, impact, creep, friction and wear. Microstructural and fractographic analyses of metals.

Alloys and phase diagrams: Phases and structural constituents. Cooling curves, 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, strain hardening (plastic deformation technology basics), grain refinement, precipitation and dispersion.

Binary phase diagrams of metallic alloys. 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 according to EURONORM

Phase transformations in steels: Ferritic, prelatic, 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 Moodle 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. Visit to the metallurgy lab with practical activities.

Assessment methods

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

The final examination consists of a written test, aiming 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 and how (ii) to identify the reasons for  malfunctioning related to material features.   

The written examination consists of two parts: multiple choice test (30 questions, 4 options per question, 45 minutes) and open questions (2 questions, 60 minutes). Total examination time: 1h 45 min. Examples of questions are available in the teaching material available in the Moodle repository.

The second part of the examination material (answers to open questions) will be corrected by the teacher only if the candidate achieves at least 20 correct answers in the first part (multiple choice test). Answers to multiple choice questions will be evaluated as follows:

• +1 pt for each correct answer
• 0 pt for each missing answer
• -0,25 pt for each wrong answer

The final grade will be calculated as weighted average of the grade for each section, with the following weights:

• part 1 (multiple choice test) = 15
• part 2 - open question 1 = 10
• part 2 - open question 2 = 10

Textbooks and electronic devices are not allowed during the examination. The grade is expressed in /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.

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 blackboard. Students are encouraged to attend Metallurgy classes in order to improve their final learning outcomes. The course attendance is not mandatory and it does affect the final examination score. Visits to the Metallurgy research lab (equipment for metallographic preparation; optical and stereo microscopy with image analyser; hardness testers; tensile tester) are scheduled each year.

Office hours

See the website of Carla Martini