course 1.ppt
Post on 02-Jun-2018
219 Views
Preview:
TRANSCRIPT
-
8/10/2019 Course 1.ppt
1/31
COURSE1
MATERIALS SCIENCE
Prof.Dr.Eng. Brndua GHIBAN
1
11/3/2014
Materials. Classification
Crystalline structure
-
8/10/2019 Course 1.ppt
2/31
CONTACTDATA:
Prof.Dr.Eng. Brndua GHIBAN
Departament METALLIC MATERIALS SCIENCE, PHYSICAL METALLURGY
Consultation: HALL JK 114, THURSDAY 10-12
11/3/2014
2
ACTIVITATY during SEMESTRY
Final
VERIFICA-
TIONNote
presence
course
5p
Note access
moodle
platform
10p
Note
laboratory
presence
0
Note
course
manuscript
5p
Note
Laboratory
colloquium
20p
Note
semestry
evaluation
20p40 points
60 points
STUDENTSEVALUATION
-
8/10/2019 Course 1.ppt
3/31
MATERIALS SCIENCE11/3/2014
3
is an interdisciplinary science at the border between
mathematics -physics- chemistry- technique, dealingwith complex characterization of materials, the study
of correlations, functional links between chemical
composition, structure, properties, technology
(design, machining, heat treatment) and technical
use of the materials in order to establish laws, rules,criteria and models that will produce
materials with
predetermined properties (design materials),
optimum selection of material for a rational and
scientific substantiation of materials technology.
-
8/10/2019 Course 1.ppt
4/31
Materials define the development of human society
11/3/2014
4
-
8/10/2019 Course 1.ppt
5/31
EXAMPLEOFEVOLUTIONOFMATERIALS
USEDINAEROGASTURBINES11/3/2014
5
-
8/10/2019 Course 1.ppt
6/31
Utilization of the materials
depends on the properties,
resources, cost price,
workability and compatibilitywith the environment
11/3/2014
6
-
8/10/2019 Course 1.ppt
7/31
MATERIALSCLASSIFICATION11/3/2014
7
-
8/10/2019 Course 1.ppt
8/31
11/3/2014
8
Organic Materials(carbon, hidrogen, oxigen, nitrogen)
Inorganic MaterialsSimple
Complexe (salts, oxides, halides)
After chemicalcomposition
After the state of
aggregation
MATERIALSCLASSIFICATION
-
8/10/2019 Course 1.ppt
9/31
Interatomic Bonds
1
1/3/2014
9
Ionic Bond
Typically, the metal has a 1,2,3 electron valence shell, and has a non-
metallic 5, 6, 7, electrons in the valence shell. Steady state occurs through
the sharing of electrons in the valence shell. Solid materials with Ionic
bonds are :
Hard materials
Insulating substances,
Transparent
Brittle,
High melting point
-
8/10/2019 Course 1.ppt
10/31
Covalent bonds
1
1/3/2014
10
Covalent bonds occur between atoms of metals. They have four or more
electrons to the valence layer. To form a new connection would require
very high energy, either for extraction or for adding a new electron. Steady
state occurs through the sharing of electrons in the valence shell. The
solids that are covalent :
Hard materials
Good insulation
Transparent
Brittle, deformable
-
8/10/2019 Course 1.ppt
11/31
Metallic Bonds
1
1/3/2014
11
The metallic bonds may appear between the metal atoms. These materials have three
valence shell electrons. When an item has a 1,2,3 valence electrons per layer, the link
established is very poor (e.g aluminum). The connection is formed between a lot of
metal atoms, creating a "cloud of electrons" as a negative value and "frame", with a
positive valence. Solid materials with metallic bonds are
Bohr Model for metal
Good electrical and thermal conductor
Opaque
Relatively ductile
-
8/10/2019 Course 1.ppt
12/31
VAN DER WAALS BONDS
1
1/3/2014
12
Van der Waals bonds occur, with few exceptions, in all materials, but
usually in plastics and polymers. These materials have very longmolecular chains, link atomic carbon and other atoms, hydrogen,
nitrogen, oxygen, fluorine. Covalent bonds between the molecules are
very strong and break under extreme conditions. Polymers can be
classified as behavior heating :
Thermoplastic polymers which
soften or liquefy the hot
Thermoset polymers with irreversiblereaction,
Elastomers, with intermediate
behavior.
-
8/10/2019 Course 1.ppt
13/31
1
1/3/2014
13
MATERIALSCLASSIFICATION
After the nature of the
atomic bonds
Metallic Materials
Ceramic Materials
Polymeric Materials
Composite Materials
-
8/10/2019 Course 1.ppt
14/31
Metallic Materials
1
1/3/2014
14
Very good thermal and electrical conductivity,
Good deformability,
Excellent ferromagnetic properties,
Hardening capacity by applying heat treatments.
-
8/10/2019 Course 1.ppt
15/31
CERAMICMATERIALS
1
1/3/2014
15
Good optical properties,
Good thermal insulation,
High melting temperature,
Relatively inert in contact with molten metal,
Piezoelectric behavior and the ability to convert into electricity.
-
8/10/2019 Course 1.ppt
16/31
POLYMERICMATERIALS 11/3/2014
16
Excellent ductility, with high capacity to form flexible films,
Good electrical insulators,
High resistance to corrosion in aqueous solutions
(moisture resistance).
-
8/10/2019 Course 1.ppt
17/31
COMPOSITE
MATERIALS1
1/3/2014
17
Metallicmaterials
Organic
polymericmaterials
Ceramic
materials
Composite
Polymer matrix
composites reinforced
with metal
Polymer matrix
composites reinforced
with ceramics
Metal matrix
composites reinforced
with ceramics
consist of a matrix of soft material (plastic, tenacious,
ductile) which includes a hard and brittle material
filling (in the form of blades, isolated fibers or
particles).
1 + 1 = 3
-
8/10/2019 Course 1.ppt
18/31
Materials Structure
1
1/3/2014
18
Structure represents the internal architecture of a
materials system by its parts of components.
(Structure may be observed with naked eye or with glasseye)
1. Macrostructure > 10-2 cm
(Type and proportion of constituents observed by opticmicroscope)
2. Microstructure, 10-810-1cm
(Type of crystalline lattice observed by electron microscope)
3. Crystalline structure, 10-810-1 cm
(Type or chemical bond realized with valence electron of theatoms,observed by electron microscope)
4. Atomic structure, 10-8cm
(Number, cuantic numbers, electron distribution in layers,sublayers and orbitals observed by X-Rays)
5. Electronic structure of the atoms, 10-8cm
(Nature and number of nuclear particles observed by X-Rays)
6. Nuclear structure, 10-13cm
-
8/10/2019 Course 1.ppt
19/31
SCALE OF MATERLS FOR NANOTECHNOLOGY
1
1/3/2014
19
Length scale showing the nanometre in context. The length scale at the top ranges from 1m to 10 -10m, and
illustrates the size of a football compared to a carbon 60 (C60) molecule, also known as a buckyball. For
comparison the world is approximately one hundred million times larger than a football, which is in turn one
hundred million times larger than a buckyball. The section from 10-7m (100nm) to 10-9m (1nm) is expanded below.
The length scale of interest for nanoscience and nanotechnologies is from 100nm down to the atomic scale -approximately 0.2nm.
-
8/10/2019 Course 1.ppt
20/31
Crystalline structure of metals and alloys
Crystalline structure and metallic bond represent the most important and decisive
characteristic of the metallic materials, main physical-chemical properties, respectively
mechanical characteristics being influenced by them.
The lower portion of a space lattice which store the symmetry of the entirenetwork is unit cell. The unit cell is defined by its parameters, which are the vectors a,
b andc (unit cell edge) and angle (between b and c), angle (between a and c) and
angle (between a and b).
Dimensional periodic repetition of the unit cell leads to obtaining of the network
space, on whose regularity and symmetry properties relies almost all metals.
Unit cell
Orderly arrangement of atoms in a real crystal is its crystalline structure;
symmetry of the crystal structure corresponds to the spatial network structure, but it
must be noted that the atoms do not occupy those positions in complete immobility,
but it vibrates (oscillates) around these positions, which leads to the real crystals with
many imperfections.
Space lattice
1
1/3/2014
20
-
8/10/2019 Course 1.ppt
21/31
Main elements which characterize the crystalline lattice
1. Lattice parameter(a,b,c,)represents the distance
between the centers of two
atoms imaginary neighbors
leading edge of the network
2. ,,angles they makebetween them and edges of
the unit cell with lattice
parameters that determine the
crystal system
cwbvaur
1
1/3/2014
21
-
8/10/2019 Course 1.ppt
22/31
3. DIRECTIONSOFHIGHDENSITYINATOMS
Miller index - for directions are , ,
- for family directions are [110] [111].
Crystalline direction is defined through three index (u,v,w), whichrepresent the smallest entire coordinates of a vector which passthrough origin of the axes of a cell and is parallel with the crystallinedirection.
those directions in which two or more atoms
are tangent between them.1
1/3/2014
22
-
8/10/2019 Course 1.ppt
23/31
Notation for - atomic planes are (111), (100), etc.
- and of planes family {111}, {100}, etc.
Crystallographic plane is defined by the indices h, k, l, which represents
the inverse value of the full segments which form the intersection of theplane with the coordinate axes.
1
1/3/2014
23
4. Planes with high atomic density {111}
those planes formed by atoms that have the
most compact settlement (the most compact
planes are those in which each atom is
surrounded by six atoms willing hexagonal.
-
8/10/2019 Course 1.ppt
24/31
Represent the number of atoms which
are at a minimum distance of a given
atom. With the increasing amount of
coordination number, atomic radius
increases.
C = 12 atoms
C= 8 atoms
C = 12 atoms
5. Coordination n umber, C,
1
1/3/2014
24
FCC
BCC
HC
-
8/10/2019 Course 1.ppt
25/31
6. Number of atoms A, which belong to a unit cell
1
1/3/2014
25
FCC
BCC
HC
-
8/10/2019 Course 1.ppt
26/31
7. Close-packed factor
1
1/3/2014
26
cellunitofvolum
atomofvolumecellunitperatomsofnumber ))((
%52100.3
8
3.
3
4
r
r
%68100.
3.
3
3
4
3.
3
4.2
r
r
%74100.3
.
3
)22(
3.3
4.4
r
r
Simple Cube
Body cubic centered
Face cubic centered
-
8/10/2019 Course 1.ppt
27/31
The main crystalline systems
Cristalline system Crystalline parameters Cristalline lattice
Angles Distances
Cube = = 90 a = b= c Cubicsimpl
Cubiccu volum centrat (CVC)
Cubiccufeecentrate (CFC)
Tetragonal = = = 90 a= bc Tetragonalsimpl
Tetragonalcu volum centrat (TVC)
Orthorombic = = = 90 abc Simple Orthorombic
Body centered orthorombic
Base centered orthorombic
Face centered orthorombic
1
1/3/2014
27
-
8/10/2019 Course 1.ppt
28/31
Cristalline system Crystalline parameters Cristalline lattice
Angles Distances
Rombohedric = = 90 a= b= c Simple Rombohedric
Hexagonal = = 90
= 120
a= bc Simple Hexagonal
Compact Hexagonal (HC)
Monoclinic = = 90 abc Simple monoclinic
Base centered monoclinic
Triclinic 90 abc Simple triclinic
1
1/3/2014
28
-
8/10/2019 Course 1.ppt
29/31
BCC
Unit cel ls for the mos t frequent metals:
1
1/3/2014
29
-
8/10/2019 Course 1.ppt
30/31
FCC
1
1/3/2014
30
Unit cel ls for the mos t frequent metals:
-
8/10/2019 Course 1.ppt
31/31
HC11/3/2014
31
Unit cel ls for the mos t frequent metals:
top related