11diktat Material Teknik

MS 2130 Lecture Note by Husaini ArdyMS 2130 Lecture Note by Husaini Ardy

MATERIAL TEKNIKMATERIAL TEKNIK(MS 2130)(MS 2130)

Dr. Dr. irir. . HusainiHusaini ArdyArdyLaboratoriumLaboratorium TeknikTeknik MetalurgiMetalurgiProgram Program StudiStudi TeknikTeknik MesinMesinInstitutInstitut TeknologiTeknologi BandungBandung

[email protected]@melsa.net.idMobile : 081Mobile : 081--123123--678678--22


InformasiInformasi PentingPenting

BukuBuku AcuanAcuan ::–– William D. William D. CallisterCallister, , Fundamentals of Materials Fundamentals of Materials

Science and EngineeringScience and Engineering, John Wiley, 2003., John Wiley, 2003.

UjianUjian ::–– UTSUTS--1 = 50%1 = 50%–– UTSUTS--2 = 50%2 = 50%

KehadiranKehadiran > 80%> 80%


1. PENDAHULUAN1. PENDAHULUAN

Historical PerspectiveHistorical PerspectiveMaterials Science and Engineering Materials Science and Engineering Why study Material Science and Why study Material Science and EngineeringEngineeringClassification of MaterialsClassification of MaterialsModern Materials NeedModern Materials Need


1.1 Historical Perspective1.1 Historical Perspective

Civilization has been divided based on the ability to produce Civilization has been divided based on the ability to produce and manipulate materials : Stone age, Bronze age, Iron ageand manipulate materials : Stone age, Bronze age, Iron age

Everyday life is affected one to another by the materialsEveryday life is affected one to another by the materials

Materials utilization is a selection process among the Materials utilization is a selection process among the available materials, sometime is limited, or not available et alavailable materials, sometime is limited, or not available et alll

Materials limited designMaterials limited design

Relationship between structures and properties of materialsRelationship between structures and properties of materials


1.2 Materials Science and Eng.1.2 Materials Science and Eng.

Materials Science : investigating the relationship Materials Science : investigating the relationship between structure between structure –– propertiesproperties

Materials Engineering : Engineered the structure to Materials Engineering : Engineered the structure to obtain a set of propertiesobtain a set of properties

Structure :Structure :–– Atomic scale (atomic arrangement)Atomic scale (atomic arrangement)–– Microstructure (viewed by microscope)Microstructure (viewed by microscope)–– Macrostructure (viewed by naked eye)Macrostructure (viewed by naked eye)

Property : the response of material to a specific stimulus. Property : the response of material to a specific stimulus. It is independent of geometry and size.It is independent of geometry and size.


Property of MaterialsProperty of MaterialsMechanical (stimulus : deformation):Mechanical (stimulus : deformation):–– Strength, Hardness,Strength, Hardness,……....

Electrical (stimulus : electric field) :Electrical (stimulus : electric field) :–– Conductivity, Dielectric constantConductivity, Dielectric constant

Thermal (stimulus : heat) :Thermal (stimulus : heat) :–– Conductivity, heat capacityConductivity, heat capacity

Magnetic (stimulus : magnetic field) :Magnetic (stimulus : magnetic field) :–– Magnetic strengthMagnetic strength

Optical (stimulus : light or electromagnetic wave) :Optical (stimulus : light or electromagnetic wave) :–– Refraction indexRefraction index

Deteriorative (stimulus : environment) :Deteriorative (stimulus : environment) :–– Corrosion resistanceCorrosion resistance


LINEAR RELATIONSHIPLINEAR RELATIONSHIP

PROCESSING

STRUCTURE

PROPERTIES

PERFORMANCE


WHY STUDY MS&EWHY STUDY MS&E

Materials selections basis:Materials selections basis:–– Operating conditionsOperating conditions–– Performance during servicePerformance during service–– CostCost

Wide range of material availableWide range of material available

Compromise all of the aspects, lead to optimum material Compromise all of the aspects, lead to optimum material selectionselection

Evaluation of materials performance during serviceEvaluation of materials performance during service

In some cases a new material has to be developedIn some cases a new material has to be developed


CLASSIFICATION OF MATERIALSCLASSIFICATION OF MATERIALS

Based on structure :Based on structure :–– MetalMetal–– CeramicCeramic–– PolymerPolymer

Another Group :Another Group :–– SemiconductorSemiconductor–– CompositeComposite–– BiomaterialsBiomaterials


Metals :Metals :–– Large number of free Large number of free

electronelectron–– Electrical and heat Electrical and heat

conductivityconductivity–– Not transparentNot transparent–– Shiny polished surfaceShiny polished surface–– High strength and High strength and

deformabledeformable

Ceramics :Ceramics :–– Consists of oxides, nitrides, Consists of oxides, nitrides,

and carbidesand carbides–– Electric and heat insulatorElectric and heat insulator–– High temperature strengthHigh temperature strength–– Brittle at room temperatureBrittle at room temperature

Polymer :Polymer :–– Organic compounds based Organic compounds based

on carbon, hydrogen, on carbon, hydrogen, oxygen, and other nonoxygen, and other non--metallic elementsmetallic elements

–– Very large molecule Very large molecule structurestructure

–– Low density and flexibleLow density and flexible

Composite :Composite :–– Consists of two or more Consists of two or more

materialsmaterials–– Obtain a good properties Obtain a good properties

from each componentfrom each component–– Polymer matrix compositePolymer matrix composite–– Metal matrix compositeMetal matrix composite–– Ceramic matrix compositeCeramic matrix composite


Semiconductor :Semiconductor :–– Properties between electric Properties between electric

insulator and electric insulator and electric conductorconductor

–– Properties is highly affected Properties is highly affected by small amount of by small amount of impuritiesimpurities

Biomaterials :Biomaterials :–– Implant to human body for Implant to human body for

replacement of diseases or replacement of diseases or damaged body partsdamaged body parts

–– Must not produce toxic Must not produce toxic substancesubstance

–– Must be compatible to the Must be compatible to the body tissuebody tissue

Advanced Materials :Advanced Materials :–– Materials for highMaterials for high--tech tech

applicationsapplications–– Has a superior propertiesHas a superior properties–– Very expensiveVery expensive


2. STRUCTURE OF METALS 2. STRUCTURE OF METALS AND CERAMICSAND CERAMICS


Fundamental ConceptFundamental Concept

Atoms, Unit Cell, Atoms, Unit Cell, Grains, Bulk MaterialGrains, Bulk Material

Crystalline MaterialsCrystalline Materials

NonNon--Crystalline Crystalline Materials Materials (Amorphous)(Amorphous)


Metallic Crystal StructureMetallic Crystal Structure


Body Centered CubicBody Centered Cubic

Coordination number = 8Coordination number = 8APF = APF = volvol atom in unit cellatom in unit cell

volvol unit cellunit cellAtomic packing factor = 0.68Atomic packing factor = 0.68Number of atom per unit cell = 2Number of atom per unit cell = 2

Unit cell size, Unit cell size, 3

4Ra =


Face Centered CubicFace Centered Cubic

Coordination number = 12Coordination number = 12APF = 0.74APF = 0.74Number of atom per unit cell = 4Number of atom per unit cell = 4Unit cell size, Unit cell size, 22Ra =


Hexagonal CloseHexagonal Close--PackedPackedNumber of atom per unit cell = 6

Ratio c/a = 1.633 (ideal)

Coordination number = 12

Atomic packing factor = 0.74


Theoretical density of Theoretical density of metals :metals :

–– ρρ = density= density–– n = number of atom per n = number of atom per

unit cell (atom)unit cell (atom)–– A = atomic weight A = atomic weight

(gram/mol)(gram/mol)–– VVcc = unit cell volume (cm= unit cell volume (cm33))–– NNAA = Avogadro Number = = Avogadro Number =

6.023 x 106.023 x 102323 atom/molatom/mol

Example :Example :

Copper, FCC structure, Copper, FCC structure, atomic radius = 1.28 A, atomic radius = 1.28 A, atomic weight = 63.5 g/mol.atomic weight = 63.5 g/mol.

n = 4, Vn = 4, VCC = (2 R = (2 R √√22))33 cmcm33

Literature data : Literature data : ρρ = 8.94 = 8.94 gr/cmgr/cm33

AC NVAn

=ρ

( )38 21028.116

5.634

xxx

xNVAn

AC −==ρ

389.8cm

gram=ρ


Ceramics StructureCeramics Structure

Composed of two elements or moreComposed of two elements or moreMore complex crystal structure than metalsMore complex crystal structure than metalsFor ionic bonding :For ionic bonding :–– Metallic ion : Metallic ion : cationcation–– NonNon--metallic ion : anionmetallic ion : anion–– The crystal must be neutralThe crystal must be neutral–– Positive charge = negative chargePositive charge = negative charge


Cesium Chloride Structure :Cesium Chloride Structure :–– The coordination number = The coordination number =

88–– CationCation--anion radius ratio = anion radius ratio = –– 0.732 0.732 –– 1.01.0–– CsClCsCl

Rock Salt structure :-The coordination number = 6

-Cation-anion radius ratio =

0.414 - 0.732

-NaCl, MgO, MnS, LiF, FeO


Zinc Blend structure :-The coordination number = 4


0.225 - 0.414

-ZnS, ZnTe, SiC

AmXp structure :-The coordination number = 8


0.732 – 1.0

-CaF2, UO2, PuO2, ThO2


AAmmBBnnXXpp structurestructure


CRYSTALLOGRAPHIC PLANE (CUBIC)CRYSTALLOGRAPHIC PLANE (CUBIC)


CRYSTALLOGRAPHIC PLANES (HEXAGONAL)CRYSTALLOGRAPHIC PLANES (HEXAGONAL)

i = - (h + k)


CRYSTALLOGRAPHIC DIRECTIONCRYSTALLOGRAPHIC DIRECTION


POLYCRYSTALLINE MATERIALPOLYCRYSTALLINE MATERIAL

Atoms ==>> Unit Cell ==>> Crystal/Grain ==>> Bulk Material


NONCRYSTALLINE MATERIAL NONCRYSTALLINE MATERIAL (AMORPHOUS)(AMORPHOUS)

Crystalline : Systematic and regular arrangement of atoms


STRUCTURE OF POLYMERSTRUCTURE OF POLYMER


TYPE OF POLYMERTYPE OF POLYMER

Natural Polymer :Natural Polymer :–– Wood, Rubber, Cotton, Wool, Silk, LeatherWood, Rubber, Cotton, Wool, Silk, Leather

Synthetic Polymer :Synthetic Polymer :–– PVC, PTFE, PPPVC, PTFE, PP

Polymer : Polymer : –– is a macromolecules of hydrocarbonis a macromolecules of hydrocarbon–– Repetition of the Repetition of the ““mermer”” unitunit–– Example : ethylene (CExample : ethylene (C22HH44) can be synthesized to poly) can be synthesized to poly--ethylene ethylene

(polymer)(polymer)


Chemistry of Polymer MoleculesChemistry of Polymer Molecules

Ethylene (CEthylene (C22HH44):):

Ethylene gas is synthesized (P, Ethylene gas is synthesized (P, T) : T) :

FutherFuther reaction :reaction :


Polyethylene


Polytetraflourethylene

Polyvinylchloride

Polypropylene


Molecular WeightMolecular Weight

Large molecules consists of large number of Large molecules consists of large number of mermer units.units.Not all of the chain has the same molecular weightNot all of the chain has the same molecular weightResults in the distribution of chain length or molecular Results in the distribution of chain length or molecular weightweightMolecular weight shall be defined as : Molecular weight shall be defined as : the average the average molecular weight.molecular weight.

How to define the average molecular weight :How to define the average molecular weight :–– The The numbernumber average molecular weight, average molecular weight, MMnn

–– The The weightweight average molecular weight, Maverage molecular weight, Mww


The Number Average Molecular WeightThe Number Average Molecular Weight

Dividing the chain into a series of size rangeDividing the chain into a series of size rangeDetermining the number fraction of chain within the size Determining the number fraction of chain within the size rangerange

∑= iin MxM

xi = fraction of the chain within the size range

Mi = mean molecular weight of size range i


The weight average molecular weightThe weight average molecular weight

Weight fraction of molecules within a size rangeWeight fraction of molecules within a size range

∑= iiw MwM

wi = weight fraction of molecule within the size range

Mi = mean molecular weight of size range i


Degree of polymerization Degree of polymerization (n) :(n) :

mMn n

n =

mMn w

n =

m : mer molecular weight


Molecular ShapeMolecular Shape

Straight chain Twist and bend chain

r = end-to-end distance

Twist, bend and kink chain

- High flexibility


Molecular StructureMolecular Structure

Linear polymer :Linear polymer :–– MerMer unit are joint together in a single chainunit are joint together in a single chain–– PE, PVC, PMMC, PS, Nylon, FluorocarbonPE, PVC, PMMC, PS, Nylon, Fluorocarbon

Branched polymer :Branched polymer :–– The sideThe side--branch chains are connected to the main chainbranch chains are connected to the main chain

CrossCross--linked polymer :linked polymer :–– Adjacent linear chains are join one to another at various positiAdjacent linear chains are join one to another at various position on

by strong covalent bond by strong covalent bond –– Vulcanized rubberVulcanized rubber

Network polymer :Network polymer :–– Three dimensional network of polymerThree dimensional network of polymer–– Epoxy, PhenolEpoxy, Phenol--formaldehydeformaldehyde


Thermoplastic and Thermosetting PolymersThermoplastic and Thermosetting Polymers

Thermoplastic :Thermoplastic :–– Soften and liquefy when heated, harden when cooled Soften and liquefy when heated, harden when cooled –– Reversible process in heating and coolingReversible process in heating and cooling

Thermosetting :Thermosetting :–– Permanently hard when heated, will not soften/liquefy during Permanently hard when heated, will not soften/liquefy during

subsequent heatingsubsequent heating–– Harder and stronger than thermoplasticHarder and stronger than thermoplastic–– Better dimensional stabilityBetter dimensional stability–– Vulcanized rubber, Epoxy, Vulcanized rubber, Epoxy, PhenolicPhenolic, some polyester resin, some polyester resin


CopolymerCopolymer

Random copolymer :Random copolymer :–– Two different units are Two different units are

randomly dispersed along the randomly dispersed along the chainchain

Alternating copolymer :Alternating copolymer :–– The two The two mermer units alternate units alternate

chain positionchain position

Block copolymerBlock copolymer ::–– Identical Identical mersmers are clustered in are clustered in

blocks along the chainblocks along the chain

Graft copolymer :Graft copolymer :–– Side branches are grafted to Side branches are grafted to

the main chainthe main chain


Synthetic rubber : is an example of copolymer.Synthetic rubber : is an example of copolymer.


Polymer Polymer CrystalinityCrystalinity

Polymer Polymer crystalinitycrystalinity : the regular and repetitive array of : the regular and repetitive array of polymer molecules.polymer molecules.Polymer molecules : partially crystalline, partially Polymer molecules : partially crystalline, partially amorphousamorphousThe crystalline polymers dispersed within the amorphous The crystalline polymers dispersed within the amorphous (up to 95% of (up to 95% of crystallinitycrystallinity))Crystalline polymers : stronger and more heat resistanceCrystalline polymers : stronger and more heat resistanceAmorphous : chain disorders or misalignmentAmorphous : chain disorders or misalignmentCrystallinityCrystallinity depends on :depends on :–– Low cooling rate (need time for alignment)Low cooling rate (need time for alignment)–– Chain configuration (simple chain is easier to crystallize)Chain configuration (simple chain is easier to crystallize)


Crystalline PE

TEM image


Fringe-micelle model

Chain-folded model


Detail structure of spherulite

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