This course focuses on the basic of materials and technologies of interest for automotive and mechanical engineering. The aim of this course is to give students basic knowledge on metals and polymers and on their properties. In particular, the metallurgy module aims to correlate properties of metals and alloys to chemical composition, microstructure, and manufacturing methods with the final aim of effectively and economically select the most suitable materials and processing technologies for the realization of mechanical parts and systems.

The course will establish the fundamentals of materials behaviour, in particular to their load carrying capacity as influenced by composition, microstructure, thermal and mechanical processing. The properties of the main classes of materials are presented, in particular mechanical and thermal properties. Attention is devoted to steels and their heat-treating procedures (e.g. bulk tempering and surface thermo-chemical treatments). The quenching and ageing processes of Al and Mg alloys will be fully described. Description of applications of selected classes of steels, Al, Mg, and Cu alloys is offered, together with the main classes of polymers, aiming to guide students toward material selection, design and quality assessment.

The main aim is to supply the student with a robust background in materials, able to couple scientific and technological knowledge in a synergic way, providing general guidelines for translating scientific knowledge into technological tools for engineering design.
The student will learn:
- the relation between materials atomic nature and their properties;
- how to exploit this scientific background in controlling the material properties up to the tailoring of materials application;
- how to select materials to fulfil design requirements;
- to develop a confident approach to materials and their properties;

The student will become familiar with the mechanical and technological properties of metal alloys and the basic manufacturing technologies, so that he can build up the required fundamental knowledge for the optimum selection of metals or alloys, including manufacturing processes for the design and construction of mechanical components and structures under specified operating conditions.

The student is required to have a robust, basic knowledge of Chemistry and Physics.
It is required a basic knowledge of Material Science and Technology and Applied Chemistry and Mechanical behaviour of materials.

Module of Science and technology of materials.

Introduction on metals, polymers, basic notions on ceramics, glasses and composites.
Correlations structure/property of materials, Crystalline structure and defects, Amorphous structure, Plastic deformation. (10 hours). Mechanical and thermal properties, their relation to materials structure (20 hours). Phase diagrams (10 hours). Polymers: properties, uses and related technologies (10 hours).
Metallurgy - Metallic phases: cubic and hexagonal lattices. Interstitial and substitutional solid solutions. Hume-Rothery phases, Laves phases, carbides. The hardening mechanism of the metal alloys: strain hardening and softening, grain size, solid solution and 2nd phase precipitates.
Al alloys. Mechanical properties of biphasic alloys. Microstructure effect. Precipitation hardening of coherent and incoherent particles. G.P. zones, ƒá and ƒá¡¥ phases in Al-Cu alloys. Precipitation hardening after natural or artificial ageing. Thermo-mechanical treatments. Standards of Al-alloys. Mg and Cu alloys: principles and applications. Introduction to Ti alloys. (20 hrs.)
Thermal treatments of the steels: annealing, normalizing. Eutectoidic transformation. Curves of isothermal transformation, quenching. Martensitic transformation, Ms and Mf. Continuous cooling transformation curves. Effect of cooling rate on the microstructure and mechanical properties of the steels. Jominy test. Effect of alloying elements on the Jominy curves. Quenching cracks. Tempering and tempering embrittlement. Effect of Si, Mo and Cr. (10 hrs).
Flame and Induction surface hardening. Fundamentals and application.
Thermo-chemical treatments: endothermic and exothermic atmospheres. Quench and tempering cycles. Effect of thermo-chemical treatments for fatigue and wear resistance. Carburizing. Carbon potential of carburizing atmospheres. Influence of CO and CH4 in the carburizing. 1st and 2nd Fick¡¦s laws. Treatment time and thickness of hardened layers. Vacuum and plasma carburizing. Thermal treatments after carburizing. Nitriding. Fe-N metastable phase diagram. Leher diagram: effect of NH3/H2 mixtures and constitution of nitride phases. Surface and diffusion layers. Nitrocarburizing.
Carbon and alloyed steels: effect of alloying elements. Stainless steels: Cr influence. Austenitic, ferritic and martensitic steels. Structural steels. Hollomon-Jaffe equation. Weldability of the steels: effect of the chemical compositions. (20 hrs).

Module of Technology of metallic materials.

Overview on metallic bonding theory: electronegativity, anisotropy and allotropy, Humé-Rothery rules; substitutional/interstitial solid solutions, intermetallic and interstitial compounds; ordering. Lattice defects and their influence on strength of metals. Multiscale of microstructure and its inspection and diagnostics by microscopy. Strengthening mechanisms (solid solutions, work hardening, preciptation and dispersion, hard phases, grain refinement, texture). Physical and mechanical properties: sensitive and non sensitive properties to microstructure. Fundamentals and problems behind corrosion of metals and alloys and their protection methods; basic selection of stainless steels and non ferrous alloys for typical corrosion problems Tensile test curve; the Ludwik-Hollomon law; extraction of formability parameters from tensile test curve. (20h)
Manufacturing of metallic alloys. Casting technologies (chill casting), homogeneous/ heterogeneous nucleation and phase growth upon solidification; casting microstructure and defects, semi-solid casting; solid-state transformations. Plastic deformation forming (hot, warm, cold); stress relaxation, recrystallization, grain growth, superplastic forming; forging, rolling, extrusion; cold forming: deep drawing, hydroforming; influence of processing methods on microstructure and mechanical properties. Formability tests for sheet metals; FLD curves; powder metallurgy, electric-activated sintering; microstructure and mechanical properties of sintered components. Welding technologies , weldability, welding defects. (15h)

IRON AND IRON ALLOYS. European nomenclature of steels. Fe-Fe3C and Fe-N phase diagrams; primary and secondary production of steels; influence of alloying elements on steel properties (Mn, Cr, Si, Mo, Al, Ti, Nb); austenite, ferrite, pearlite, bainite, martensite microstucture and distinctive properties. TTT curves and CCT curves: origin, interpretation and their application to heat treatment of steels: annealing, normalizing, quenching and tempering; hardenability and Jominy test; weldability of steels; thermomechanical heat treatments: austempering and martempering. Heat treatment defects: embrittlement and residual stresses induced by cooling. Correlation between composition, microstructure, heat treatment method and mechanical properties. Surface hardening of steels: induction and laser hardening, carburizing, nitriding and carbonitriding treatments. Stainless steels. Tool steels. Selection of steels for mechanical applications: sheets and drawing quality, construction steels, spring steels, bearing steels, tool steels, valve steels.
Cast irons: European nomenclature of cast irons; equlibrium Fe-C phase diagram, microstructure and mechanical properties of grey, ductile, white cast irons; heat treatment of cast irons, austempering of cast irons; engineering applications.

NON-FERROUS METAL AND ALLOYS.
Alluminum and alluminum alloys. European nomenclature of aluminum alloys. Casting alloys: influence of alloying elements; Al-Cu, Al-Si, Al-Mg, Ti-Al phase diagrams. Manufacturing technologies: casting (die casting, gravity casting, rheocasting); methods of microstructure refinement. Wrought alloys and heat treratment: aging and overaging phenomena. Correlation between composition, microstructure, heat treatment method; typical mechanical properties and selection criteria for mechanical applications.
Brief presentation of magnesium and magnesium alloys: casting and wrought alloys; nomenclature and typical mechanical applications. Brief presentation of titanium and titanium alloys: casting and wrought alloys; nomenclature and typical mechanical applications. Brief presentation of copper and its alloys; brasses and bronzes and its main applications.

Simplified calculation of diffractograms. In laboratory: tensile, hardness and impact tests. Brittle and ductile fracture morphology observed with scanning electron microscopy. Metallography: preparation of samples. Theoretical calculation and plot of Jominy bands of steels. Numerical execises on phase diagrams, on mechanical and thermal properties of materials.

The most important topics of practical relevance will be explored as case studies through exercise and training lab. The Program CES-EDUPACK will be introduced and exploited to solve a few mechanical applications. 30 min videos on steel production and on the relationship between microstructure and mechanical properties will be shown for better insight.

W. D. Callister ¡§Scienza e Ingegneria dei Materiali: una Introduzione¡¨ ¡V EdiSES
G. Ubertalli ¡§Lecture of the Course of TMM ¡¨
Engineering Materials 1- An introd. to properties, appl. and design ¡V Michael F. Ashby / David R.H.Jones ¡V B/H ed. - 2012
Other books:
Recrystallization and Related Annealing Phenomena ¡V F.J.Humphreys and M.Hatherly ¡V Ed. Pergamon - 2004
Aluminum, Volume I: Properties, Physical Metallurgy and Phase Diagrams ¡V John F. Hatch editor - 1967
Magnesium and Magnesium alloy - ASM Specialty Handbook - 1999
The metallurgy of Tool Steel ¡V P.Payson - 1962
ASM HANDBOOK Vol. 1 to 12 - 1991
• Structure and Properties of Engineering Alloys, W.F. Smith, McGrawHill, 2^ Ed., 2004.
• R.A. Higgins - Materials for engineers and technicians: applied physical metallurgy, 6th ed., Arnold, 2006.
• M. Ashby – Materials Engineering Science Processing and Design, BH, 1st Ed., 2007
• Meyers-Chawla - Mechanical Behavior of Materials, 2nd ed., Cambridge, 2009
• Z. Marchiniak, J.L. Duncan, S.J. Hu, Mechanics of Sheet Metal Forming, BH, 2nd Ed., 2002

The overall exam is divided into two distinct parts, relating to Science and Technology of Materials (STM) and Technology of Metallic Materials
(TMM) modules respectively. It comprises a combined 2-hour written test, based on 8 questions, 4 for each module, and may include exercises similar to those solved through lectures; each correct question is equal to 3 or 4 points. Neither books nor notes are allowed during the written test. While for STM the written test is conclusive, say, at least 9 points score suffices for passing the STM exam, for TMM a subsequent oral test is additionally required. To access the oral test the student has to achieve at least 7 points in the written test. The oral test consists of one or two further questions, depending on the written test score, aimed at assessing the capability of the student to link the learned fundamentals to practical cases as well as to solve a case study of alloy selection for a specific mechanical application.

For further information please contact:
monica.ferraris@polito.it; giovanni.maizza@polito.it