MATERIALS I Professor Catalin POPA, Dr.Eng.

REFERENCES

http://www.sim.utcluj.ro/wp/ → Download cursuri: Popa Catalin; password = PopaCatalin

• H. Colan, V. C. Cândea, s.a. - Ştiinţa materialelor Vol. 1, U.T. Press 2013;

• V. Cândea, C. Popa, T. Marcu - Atlas, structuri metalografice, U.T.Press 2012;

• V.Candea, C.Popa, N.Sechel, V.Buharu – Clasificarea si simbolizarea

aliajelor feroase si neferoase, UTPress, 2010;

• C. Popa, V. Cândea, V. Şimon, D. Lucaciu, O. Rotaru - Ştiinţa biomaterialelor.

Biomateriale metalice, U.T.Press 2008;

• V.Candea, C.Popa – Initiere in Stiinta Metalelor, Bucuresti, Ed.Vega 1995;

• H.Colan, s.a. – Studiul Metalelor, Bucuresti, EDP 1983;

• D.Askeland – Introduction to Materials Science, J.Wiley & Sons, 1993

• C. Paul – Materials Science and Engineering, ASM 1991

• W. D. Callister, D. G. Rethwisch - Fundamentals of materials science and

engineering, John Wiley and Sons, 2013;

• W. F. Hosford, Elementary materials science , ASM International 2013;

• D.L. Chung - Composite materials: science and applications : functional

materials for modern technologies, Springer 2003;

INTRODUCTION TO MATERIALS SCIENCE

Materials Science : Branch of Technical Sciences that studies the

chemical composition

structure ratio for engineering materials

properties

• Age : as a science, after 1840

(optical microscope)

Nature / chemical

composition

of the material

Structure:

macrostructure (1-50x)

microstructure (50-1500x)

atoms scale (0.1 nm)

Manufacturing

technology

Properties chemical

physical

mechanical

USES

Content of the lecture course Introduction to Materials Science. Classes of engineering materials

Properties of materials.

Corrosion resistance. Corrosion protection methods.

Interatomic bonding. Crystalline and amorphous structure.

Crystallisation of metals.

Plastic deformation of metals.

Cold hardening, recrystallisation. Fracture.

Alloys theory.

Fe-C diagram. Unalloyed steels. Foundry cast irons.

Heat treatments.

Alloy steels.

Non-ferrous alloys: Al and Cu based alloys.

Polymers.

Ceramics.

Composite materials.

Properties of materials

• Mechanical

• Physical

• Chemical

Technological Machinability

Weldability

Castability

[ Formability ]

…

→ functional properties

Materials Processing

- Casting -

Materials Processing

- Plastic forming -

Forging (hot)

Materials Processing

- Plastic forming -

Rolling (hot)

Materials Processing

- Plastic forming -

Wire drawing

Materials Processing

- Plastic forming -

Deep drawing

Materials Processing

- Machining-

Turning

Materials Processing

- Welding -

Electric arc welding

Materials Processing - Powder aggregation-

Materials Processing - Additive manufacturing-

Effect of structure upon properties

Ex.: graphite

Effect of structure upon properties

Ex.: graphite fibers

Effect of structure upon properties

Ex.: graphite fibers

Effect of structure upon properties

Ex.: graphite fibers

Effect of structure upon properties

Ex.: graphite nanotubes

Effect of structure upon properties

Ex.: graphene

Extremely light: surface of a football field ̴ 1g

The strongest material:

More than 130 times stronger than a high strength steel

CLASSES OF MATERIALS

A. Origin

natural (bone, rock, wood, proteins, etc.)

synthesis

Spider silk

CLASSES OF MATERIALS

B – NATURE

• Metals

• Ceramics

• Polymers

• Multimaterials

• Composites

• Multi-layered materials

C – USE

• Structural

• Functional

• Automotive

• Aerospace

• Electronics

• Optoelectronics

• Biomaterials

• Energy storage

• Sports equipment

….

METALS

• 89 in periodic table –electropositive character,

common energy levels between conduction /

valence bands;

• Practically not pure metals - alloys

contain other elements, based on (a) metal

• Most used – Fe, Al, Cu, Mg, Zn, Ti, Ni, ...

• Metallic state: electric conductors, resistivity

increases with temperature; thermal conductors;

metallic shine; thermo-electronic effect;

CERAMICS

Definition: Materials containing anorganic compounds, without metallic character.

General: contain metallic elements, combined with strong non-metallic elements (O, Cl, F, ....)

Exceptions: C, B

Classification: A. Classic (porcelain, clay, usual glass,....)

Engineering (alumina, zirconia, TiN,...)

B. Amorphous – glasses

Crystalline

POLYMERS

Definition: Macro-molecular organic materials, made of long atom chains

(C + H, O, N)

(M = 104 – 106)

Classification: thermoplasts (plastics)

thermosets

elastomers

COMPOSITES

Constituted of: matrix (majority of volume, maintains part’s shape)

+ reinforcing constituent

Classification: A. Matrix material Polimeric (Organic)

Metallic

Ceramic

B. Shape of reinforcing constituent

Fibres long short

Tissues

Particles

MULTILAYERED MATERIALS

Made of layers of different materials, strongly bonded, that

behave as a single material

Example:

skis

PROPERTIES OF MATERIALS

PHYSICAL PROPERTIES

Density metals: Li(0.53) …Mg(1.74)…Al(2.7)…Fe(7.8)… Os(22.5) [kg/m3] ceramics: Grafit(2.28)….WC(13-15.3)

polymers: 0.83 – 2.15 values related to water [kg/m3 x 10-3]

Electrical conductivity σ Metals: conductors Ag – Cu – Au – Al - ... – Mn Ceramics: insulators (in general); exceptions: C, semiconductors, superconductors Polymers: insulators (in general) exceptions: conductive polymers Thermal conductivity λ = thermal energy transferred through the material to increase the

temperature with 1K at a distance of 1m for a time of 1s; Similar to σ (in general) metals: conductors Au – Cu – Ag – Al - .... ceramics, polymers: insulators

Vm /

PHYSICAL PROPERTIES

Thermal expansion coefficient α (approx.)

In general: polymers / metals > ceramics

exceptions: invar alloys

Magnetic properties χm = magnetic susceptibility;

μ = magnetic permeability;

Materials: dia-magnetic (χm < 0) (Cu, Ag, Au, ...)

para-magnetic (χm >0, mic) (Feγ, Al, Ti, ...)

ferro-magnetic (χm >>0)

(Feα, Ni, Co, under Curie temperature)

tll 10

Glossary • Casting = turnare; • Plastic forming = deformare plastica (proces); • Forging = forjare; • Rolling = laminare; • Deep drawing = ambutisare; • Wire drawing = trefilare; • Welding = sudare; • Machining = aschiere; • Turning = strunjire; • Composite = compozit; • Part = piesa; • Strength = rezistenta (mecanica); • Stiffness = rigiditate; • Toughness = tenacitate; • Alloy = aliaj; • Steel = otel; • Multilayered material = multimaterial stratificat; • Engineering ceramic = ceramica tehnica • Thermoplast = termoplast; • Thermoset = termorigid; • Reinforcing constituent = constituent de armare;