manufacturing science part 1

Kalpakjian • SchmidManufacturing Engineering and Technology © 2001 Prentice-Hall -1

CHAPTER 1

The Structure of Metals

Kalpakjian • SchmidManufacturing Engineering and Technology © 2001 Prentice-Hall Page 1-2

Chapter 1 Outline

Figure 1.1 An outline of the topics described in Chapter 1


Body-Centered Cubic Crystal Structure

Figure 1.2 The body-centered cubic (bcc) crystal structure: (a) hard-ball model; (b) unit cell; and (c) singlecrystal with many unit cells. Source: W. G. Moffatt, et al., The Structure and Properties of Materials, Vol. 1,John Wiley & Sons, 1976.


Face-Centered Cubic Crystal Structure

Figure 1.3 The face-centered cubic (fcc) crystal structure: (a) hard-ball model; (b) unit cell; and (c) singlecrystal with many unit cells. Source: W. G. Moffatt, et al., The Structure and Properties of Materials, Vol. 1,John Wiley & Sons, 1976.


Hexagonal Close-Packed Crystal Structure

Figure 1.4 The hexagonal close-packed (hcp) crystal structure:(a) unit cell; and (b) singlecrystal with many unit cells.Source: W. G. Moffatt, et al., TheStructure and Properties ofMaterials, Vol. 1, John Wiley &Sons, 1976.


Slip and Twinning

Figure 1.5 Permanent deformation (alsocalled plastic deformation) of a singlecrystal subjected to a shear stress: (a)structure before deformation; and (b)permanent deformation by slip. The sizeof the b/a ratio influences the magnitudeof the shear stress required to cause slip.

Figure 1.6 (a) Permanent deformation of a singlecrystal under a tensile load. Note that the slip planestend to align themselves in the direction of the pullingforce. This behavior can be simulated using a deck ofcards with a rubber band around them. (b) Twinningin a single crystal in tension.


Slip Lines and Slip Bands

Figure 1.7 Schematic illustration of slip linesand slip bands in a single crystal (grain)subjected to a shear stress. A slip band consistsof a number of slip planes. The crystal at thecenter of the upper illustration is an individualgrain surrounded by other grains.


Edge and Screw Dislocations

Figure 1.8 Types of dislocations in a single crystal: (a) edge dislocation; and (b) screw dislocation.Source: (a) After Guy and Hren, Elements of Physical Metallurgy, 1974. (b) L. Van Vlack, Materials forEngineering, 4th ed., 1980.


Defects in a Single-Crystal Lattice

Figure 1.9 Schematic illustration of types of defects in a single-crystal lattice: self-interstitial, vacancy, interstitial, and substitutional.


Movement of an Edge Dislocation

Figure 1.10 Movement of an edge dislocation across the crystal lattice under a shear stress.Dislocations help explain why the actual strength of metals in much lower than that predicted bytheory.


SolidificationFigure 1.11 Schematicillustration of the stagesduring solidification ofmolten metal; each smallsquare represents a unit cell.(a) Nucleation of crystals atrandom sites in the moltenmetal; note that thecrystallographic orientationof each site is different. (b)and (c) Growth of crystals assolidification continues. (d)Solidified metal, showingindividual grains and grainboundaries; note the differentangles at which neighboringgrains meet each other.Source: W. Rosenhain.


Grain Sizes

TABLE 1.1ASTM No. Grains/mm2 Grains/mm3

–3–2–10123456789101112

1248163264128256512

1,0242,0484,0968,200

16,40032,800

0.72

5.61645128360

1,0202,9008,20023,00065,000

185,000520,000

1,500,0004,200,000


Preferred Orientation

Figure 1.12 Plastic deformation ofidealized (equiaxed) grains in aspecimen subjected to compression(such as occurs in the rolling or forgingof metals): (a) before deformation; and(b) after deformation. Note htealignment of grain boundaries along ahorizontal direction; this effect isknown as preferred orientation.


Anisotropy

Figure 1.13 (a) Schematic illustration of a crack in sheet metal that has been subjected to bulging(caused by, for example, pushing a steel ball against the sheet). Note the orientation of the crack withrespect to the rolling direction of the sheet; this sheet is anisotropic. (b) Aluminum sheet with a crack(vertical dark line at the center) developed in a bulge test; the rolling direction of the sheet was vertical.Source: J.S. Kallend, Illinois Institute of Technology.

(b)


Annealing

Figure 1.14 Schematic illustration of theeffects of recovery, recrystallization, andgrain growth on mechanical propertiesand on the shape and size of grains. Notethe formation of small new grains duringrecrystallization. Source: G. Sachs.


Homologous Temperature Ranges for VariousProcesses

TABLE 1.2Process T/TmCold workingWarm workingHot working

< 0.30.3 to 0.5> 0.6


CHAPTER 2

Mechanical Behavior, Testing, andManufacturing Properties of Materials


Relative Mechanical Properties of Materials atRoom Temperature

TABLE 2.1Strength Hardness Toughness Stiffness Strength/DensityGlass fibersGraphite fibersKevlar fibersCarbidesMolybdenumSteelsTantalumTitaniumCopperReinforcedReinforcedThermoplasticsLead

DiamondCubic boron nitrideCarbidesHardened steelsTitaniumCast ironsCopperThermosetsMagnesiumthermosetsthermoplasticsLeadRubbers

Ductile metalsReinforced plasticsThermoplasticsWoodThermosetsCeramicsGlassCeramicsReinforcedThermoplasticsTinThermoplastics

DiamondCarbidesTungstenSteelCopperTitaniumAluminumTantalumplasticsWoodThermosets

Reinforced plasticsTitaniumSteelAluminumMagnesiumBerylliumCopper


Tensile-Test Specimen and Machine

(b)

Figure 2.1 (a) A standard tensile-test specimen before and after pulling, showing original and finalgage lengths. (b) A typical tensile-testing machine.


Stress-Strain Curve

Figure 2.2 A typical stress-strain curve obtained from atension test, showing variousfeatures.


Mechanical Properties of Various Materials atRoom Temperature

TABLE 2.2 Mechanical Properties of Various Materials at Room Temperature

Metals (Wrought) E (GPa) Y (MPa) UTS (MPa)

Elongationin 50 mm

(%)Aluminum and its alloysCopper and its alloysLead and its alloysMagnesium and its alloysMolybdenum and its alloysNickel and its alloysSteelsTitanium and its alloysTungsten and its alloys

69–79105–150

1441–45

330–360180–214190–20080–130350–400

35–55076–1100

14130–30580–2070

105–1200205–1725344–1380550–690

90–600140–1310

20–55240–38090–2340345–1450415–1750415–1450620–760

45–465–350–921–5

40–3060–565–225–7

0Nonmetallic materialsCeramicsDiamondGlass and porcelainRubbersThermoplasticsThermoplastics, reinforcedThermosetsBoron fibersCarbon fibersGlass fibersKevlar fibers

70–1000820–1050

70-800.01–0.11.4–3.4

2–503.5–17

380275–415

73–8562–117

———————————

140–2600—

140—

7–8020–12035–170

35002000–30003500–4600

2800

0———

1000–510–1

00000

Note: In the upper table the lowest values for E, Y, and UTS and the highest values for elongation are for pure metals.Multiply gigapascals (GPa) by 145,000 to obtain pounds per square in. (psi), megapascals (MPa) by 145 to obtain psi.


Loading and Unloading of Tensile-TestSpecimen

Figure 2.3 Schematic illustration of theloading and the unloading of a tensile- testspecimen. Note that, during unloading,the curve follows a path parallel to theoriginal elastic slope.


Elongation versus % Area Reduction

Figure 2.4Approximaterelationshipbetween elongationand tensilereduction of areafor various groupsof metals.


Construction of True Stress-True Strain Curve

Figure 2.5 (a) Load-elongationcurve in tension testing of astainless steel specimen. (b)Engineering stress-engineeringstrain curve, drawn from the datain Fig. 2.5a. (c) True stress-truestrain curve, drawn from the datain Fig. 2.5b. Note that this curvehas a positive slope, indicatingthat the material is becomingstronger as it is strained. (d) Truestress-true strain curve plotted onlog-log paper and based on thecorrected curve in Fig. 2.5c. Thecorrection is due to the triaxialstate of stress that exists in thenecked region of a specimen.


Typical Values for K and n at RoomTemperature

TABLE 2.3K (MPa) n

Aluminum1100–O2024–T46061–O6061–T67075–O

Brass70–30, annealed85–15, cold-rolled

Cobalt-base alloy, heat-treatedCopper, annealedSteel

Low-C annealed4135 annealed4135 cold-rolled4340 annealed304 stainless, annealed410 stainless, annealed

180690205410400

900580

2070315

53010151100640

1275960

0.200.160.200.050.17

0.490.340.500.54

0.260.170.140.150.450.10


True Stress-True Strain Curves

Figure 2.6 True stress-truestrain curves in tension atroom temperature forvarious metals. The curvesstart at a finite level ofstress: The elastic regionshave too steep a slope to beshown in this figure, and soeach curve starts at theyield stress, Y, of thematerial.


Temperature Effects on Stress-Strain Curves

Figure 2.7 Typical effects of temperatureon stress-strain curves. Note thattemperature affects the modulus ofelasticity, the yield stress, the ultimatetensile strength, and the toughness (areaunder the curve) of materials.


Typical Ranges of Strain and Deformation Rate inManufacturing Processes

TABLE 2.4

Process True strainDeformation rate

(m/s)Cold working

Forging, rollingWire and tube drawing

Explosive formingHot working and warm working

Forging, rollingExtrusion

MachiningSheet-metal formingSuperplastic forming

0.1–0.50.05–0.50.05–0.2

0.1–0.52–51–10

0.1–0.50.2–3

0.1–1000.1–10010–100

0.1–300.1–1

0.1–1000.05–2

10-4

-10-2


Effect of Strain Rate on Ultimate TensileStrength

Figure 2.8 The effect of strainrate on the ultimate tensilestrength for aluminum. Notethat, as the temperatureincreases, the slopes of thecurves increase; thus, strengthbecomes more and moresensitive to strain rate astemperature increases. Source:J. H. Hollomon.


Disk and Torsion-Test Specimens

Figure 2.9 Disk test on a brittlematerial, showing the directionof loading and the fracture path.

Figure 2.10 Typical torsion-testspecimen; it is mounted between thetwo heads of a testing machine andtwisted. Note the shear deformation ofan element in the reduced section ofthe specimen.


Bending

Figure 2.11 Two bend-testmethods for brittle materials: (a)three-point bending; (b) four-point bending. The areas on thebeams represent the bending-moment diagrams, described intexts on mechanics of solids.Note the region of constantmaximum bending moment in(b); by contrast, the maximumbending moment occurs only atthe center of the specimen in(a).


Hardness Tests

Figure 2.12 Generalcharacteristics ofhardness-testingmethods and formulasfor calculatinghardness. The quantityP is the load applied.Source: H. W. Hayden,et al., The Structureand Properties ofMaterials, Vol. III(John Wiley & Sons,1965).


Brinell Testing

(c)

Figure 2.13 Indentation geometry inBrinell testing; (a) annealed metal; (b)work-hardened metal; (c) deformation ofmild steel under a spherical indenter.Note that the depth of the permanentlydeformed zone is about one order ofmagnitude larger than the depth ofindentation. For a hardness test to bevalid, this zone should be fullydeveloped in the material. Source: M. C.Shaw and C. T. Yang.


HardnessConversion

Chart

Figure 2.14 Chartfor convertingvarious hardnessscales. Note thelimited range ofmost scales.Because of themany factorsinvolved, theseconversions areapproximate.


S-N Curves

Figure 2.15 Typical S-Ncurves for two metals. Notethat, unlike steel, aluminumdoes not have an endurancelimit.


Endurance Limit/Tensile Strength versusTensile Strength

Figure 2.16 Ratio of endurance limit totensile strength for various metals, as afunction of tensile strength. Becausealuminum does not have an endurance limit,the correlation for aluminum are based on aspecific number of cycles, as is seen in Fig.2.15.


Creep Curve

Figure 2.17 Schematicillustration of a typical creepcurve. The linear segment ofthe curve (secondary) is usedin designing components for aspecific creep life.


Impact Test Specimens

Figure 2.18 Impact testspecimens: (a) Charpy;(b) Izod.


Failures of Materials and Fractures inTension

Figure 2.19 Schematic illustrationof types of failures in materials: (a)necking and fracture of ductilematerials; (b) Buckling of ductilematerials under a compressive load;(c) fracture of brittle materials incompression; (d) cracking on thebarreled surface of ductile materialsin compression.

Figure 2.20 Schematic illustration of the types offracture in tension: (a) brittle fracture in polycrystallinemetals; (b) shear fracture in ductile single crystals--seealso Fig. 1.6a; (c) ductile cup-and-cone fracture inpolycrystalline metals; (d) complete ductile fracture inpolycrystalline metals, with 100% reduction of area.


Ductile Fracture

Figure 2.21 Surface of ductilefracture in low-carbon steel,showing dimples. Fracture isusually initiated at impurities,inclusions, or preexisting voids(microporosity) in the metal.Source: K.-H. Habig and D.Klaffke. Photo by BAMBerlin/Germany.


Fracture of a Tensile-Test Specimen

Figure 2.22 Sequence of events in necking and fracture of a tensile-test specimen: (a) early stage ofnecking; (b) small voids begin to form within the necked region; (c) voids coalesce, producing aninternal crack; (d) the rest of the cross-section begins to fail at the periphery, by shearing; (e) the finalfracture surfaces, known as cup- (top fracture surface) and cone- (bottom surface) fracture.


Deformation of Soft and Hard Inclusions

Figure 2.23 Schematic illustration of the deformation of soft and hard inclusions and of their effect on voidformation in plastic deformation. Note that, because they do not comply with the overall deformation of theductile matrix, hard inclusions can cause internal voids.


Transition Temperature

Figure 2.24 Schematicillustration of transitiontemperature in metals.


Brittle Fracture Surface

Figure 2.25 Fracturesurface of steel that hasfailed in a brittle manner.The fracture path istransgranular (through thegrains). Magnification:200X. Source: Courtesyof B. J. Schulze and S. L.Meiley and PackerEngineering Associates,Inc.


Intergranular Fracture

Figure 2.26 Intergranularfracture, at two differentmagnifications. Grainsand grain boundaries areclearly visible in thismicrograph. Te fracturepath is along the grainboundaries.Magnification: left, 100X;right, 500X. Source:Courtesy of B. J. Schulzeand S. L. Meiley andPacker EngineeringAssociates, Inc.


Fatigue-Fracture Surface

Figure 2.27 Typicalfatigue-fracture surface onmetals, showing beachmarks. Magnification:left, 500X; right, 1000X.Source: Courtesy of B. J.Schulze and S. L. Meileyand Packer EngineeringAssociates, Inc.


Reduction in Fatigue Strength

Figure 2.28 Reductions in thefatigue strength of cast steelssubjected to various surface-finishing operations. Note that thereduction becomes greater as thesurface roughness and the strengthof the steel increase. Source: M.R. Mitchell.


Residual Stresses

Figure 2.29 Residual stresses developed in bending a beam having a rectangular cross-section. Note that thehorizontal forces and moments caused by residual stresses in the beam must be balanced internally. Because ofnonuniform deformation during metalworking operations, most parts develop residual stresses.


Distortion of Parts with Residual Stresses

Figure 2.30 Distortion of parts, with residual stresses, after cutting or slitting: (a) flatsheet or plate; (b) solid round rod; (c) think-walled tubing or pipe.


CHAPTER 3

Physical Properties of Materials


Physical Properties of Selected Materials atRoom Temperature

TABLE 3.1 Physical Properties of Selected Materials at Room TemperatureMetal Density

(kg/m3)

Melting Point(°C)

Specific heat(J/kg K)

Thermal conductivity(W/m K)

AluminumAluminum alloysBerylliumColumbium (niobium)CopperCopper alloysIronSteelsLeadLead alloysMagnesiumMagnesium alloysMolybdenum alloysNickelNickel alloysTantalum alloysTitaniumTitanium alloysTungstenZincZinc alloys

27002630–2820

185485808970

7470–89407860

6920–913011,350

8850–11,3501745

1770–178010,2108910

7750–885016,6004510

4430–470019,2907140

6640–7200

660476–654

127824681082

885–12601537

1371–1532327

182–326650

610–62126101453

1110–145429961668

1549–16493410419

386–525

900880–920

1884272385

377–435460

448–502130

126–18810251046276440

381–544142519

502–544138385402

222121–239

14652393

29–23474

15–5235

24–46154

75–13814292

12–635417

8–12166113

105–113

NonmetallicCeramicsGlassesGraphitePlasticsWood

2300–55002400–27001900–2200900–2000400–700

—580–1540

—110–330

—

750–950500–850

8401000–20002400–2800

10–170.6–1.7

5–100.1–0.40.1–0.4


Physical Properties of Material

TABLE 3.2 Physical Properties of Materials, in Descending OrderDensity Melting point Specific heat Thermal

conductivityThermalexpansion

Electricalconductivity

PlatinumGoldTungstenTantalumLeadSilverMolybdenumCopperSteelTitaniumAluminumBerylliumGlassMagnesiumPlastics

TungstenTantalumMolybdenumColumbiumTitaniumIronBerylliumCopperGoldSilverAluminumMagnesiumLeadTinPlastics

WoodBerylliumPorcelainAluminumGraphiteGlassTitaniumIronCopperMolybdenumTungstenLead

SilverCopperGoldAluminumMagnesiumGraphiteTungstenBerylliumZincSteelTantalumCeramicsTitaniumGlassPlastics

PlasticsLeadTinMagnesiumAluminumCopperSteelGoldCeramicsGlassTungsten

SilverCopperGoldAluminumMagnesiumTungstenBerylliumSteelTinGraphiteCeramicsGlassPlasticsQuartz


SpecificStrength and

SpecificStiffness

Figure 3.1 Specificstrength (tensilestrength/density) andspecific stiffness (elasticmodulus/density) forvarious materials atroom temperature. (Seealso Chapter 9.) Source:M.J. Salkind.


Specific Strength versus Temperature

Figure 3.2 Specific strength (tensile strength/density) for a variety of materials as afunction of temperature. Note the useful temperature range for these materials and thehigh values for composite materials.


CHAPTER 4

Metal Alloys: Their Structure andStrengthening by Heat Treatment


Induction-Hardened Surface

Figure 4.1 Cross-section ofgear teeth showinginduction-hardenedsurfaces. Source: TOCCODiv., Park-Ohio Industries,Inc.


Chapter 4 Outline

Figure 4.2 Outline of topics described in Chapter 4.


Two-Phase System

Figure 4.3 (a) Schematic illustration of grains, grain boundaries, and particles dispersed throughoutthe structure of a two-phase system, such as a lead-copper alloy. The grains represent lead in solidsolution in copper, and the particles are lead as a second phase. (b) Schematic illustration of a two-phase system consisting of two sets of grains: dark, and light. The dark and the light grains haveseparate compositions and properties.


Cooling Curve

Figure 4.4 Cooling curve forthe solidification of puremetals. Note that freezing takesplace at a constant temperature;during freezing the latent heatof solidification is given off.


Nickel-Copper Alloy Phase Diagram

Figure 4.5 Phasediagram for nickel-copper alloy systemobtained at a slowrate of solidification.Note that pure nickeland pure copper eachhas one freezing ormelting temperature.The top circle on theright depicts thenucleation ofcrystals. The secondcircle shows theformation ofdendrites (seeSection 10.2). Thebottom circle showsthe solidified alloy,with grainboundaries.


Mechanical Properties of Copper-Nickel andCopper-Zinc Alloys

Figure 4.6 Mechanicalproperties of copper-nickeland copper-zinc alloys as afunction of theircomposition. The curvesfor zinc are short, becausezinc has a maximum solidsolubility of 40% in copper.Source: L. H. Van Vlack;Materials for Engineering.Addison-WesleyPublishing Co., Inc., 1982.


Lead-Tin Phase Diagram

Figure 4.7 Thelead-tin phasediagram. Note thatthe composition ofthe eutectic point forthis alloy is 61.9%Sn-38.1% Pb. Acomposition eitherlower or higher thanthis ratio will have ahigher liquidustemperature.


Iron-Iron Carbide Phase Diagram

Figure 4.8 The iron-ironcarbide phase diagram.Because of theimportance of steel as anengineering material, thisdiagram is one of themost important of allphase diagrams.


Austenite, Ferrite, and Martensite

Figure 4.9 The unit cells for (a) austenite, (b) ferrite, and (c) martensite. The effect of percentage ofcarbon (by weight) on the lattice dimensions for martensite is shown in (d). Note the interstitial positionof the carbon atoms (see Fig. 1.9). Note, also, the increase in dimension c with increasing carbon content;this effect causes the unit cell of martensite to be in the shape of a rectangular prism.


Iron-Carbon Alloy Above and Below EutectoidTemperature

Figure 4.10 Schematic illustrationof the microstructures for an iron-carbon alloy of eutectoidcomposition (0.77% carbon), aboveand below the eutectoid temperatureof 727 °C (1341 °F).


Pearlite Microstructure

Figure 4.11 Microstructure ofpearlite in 1080 steel, formedfrom austenite of eutectoidcomposition. In this lamellarstructure, the lighter regions areferrite, and the darker regions arecarbide. Magnification: 2500X.Source: Courtesy of USXCorporation.


Extended Iron-Carbon Phase Diagram

Figure 4.12 Phase diagram for the iron-carbon system with graphite (insteadof cementite) as the stable phase. Note that this figure is an extended versionof Fig. 4.8.


Microstructures for Cast Irons

(a) (b) (c)

Figure 4.13 Microstructure for cast irons. Magnification: 100X. (a) Ferritic gray iron with graphite flakes. (b)Ferritic Ductile iron (nodular iron), with graphite in nodular form. (c) Ferritic malleable iron; this cast ironsolidified as white cast iron, with the carbon present as cementite, and was heat treated to graphitize the carbon.Source: ASM International.


Austenite toPearlite

Transformation

Figure 4.14 (a) Austenite-to-pearlite transformationof iron-carbon alloy as afunctionof time andtemperature. (b)Isothermal transformationdiagram obtained from (a)for a transformationtemperature of 675 °C(1247 °F). (continued)


Austenite to Pearlite Transformation (cont.)

Figure 4.14 (c) Microstructuresobtained for a eutectoid iron-carbonalloy as a function of cooling rate.Source: ASM International.


Hardness and Toughness of Annealed Steels

Figure 4.15 (a) and (b) Hardness and (c) toughness for annealed plain-carbon steels, as a function of carbideshape. Carbides in the pearlite are lamellar. Fine pearlite is obtained by increasing the cooling rate. Thespheroidite structure has spherelike carbide particles. Note htat the percentage of pearlite begins to decreaseafter 0.77% carbon. Source: L. H. Van Vlack; Materials for Engineering. Addison-Wesley Publishing Co.,Inc., 1982.


Mechanical Properties of Annealed Steels

Figure 4.16 Mechanical properties of annealed steels, as a function of composition and microstructure. Note(in (a)) the increase in hardness and strength and (in (b)) the decrease in ductility and toughness, withincreasing amounts of pearlite and iron carbide. Source: L. H. Van Vlack; Materials for Engineering.Addison-Wesley Publishing Co., Inc., 1982.


Eutectoid Steel Microstructure

Figure 4.17 Microstructureof eutectoid steel.Spheroidite is formed bytempering the steel at 700 °C(1292 °F). Magnification:1000X. Source: Courtesy ofUSX Corporation.


Martensite

(b)

Figure 4.18 (a) Hardness of martensite, as a function of carbon content. (b) Micrograph of martensitecontaining 0.8% carbon. The gray platelike regions are martensite; they have the same composition as theoriginal austenite (white regions). Magnification: 1000X. Source: Courtesy of USX Corporation.


Hardness of Tempered Martensite

Figure 4.19 Hardnessof temperedmartensite, as afunction of temperingtime, for 1080 steelquenched to 65 HRC.Hardness decreasesbecause the carbideparticles coalesce andgrow in size, therebyincreasing theinterparticle distanceof the softer ferrite.


End-QuenchHardenability

Test

Figure 4.20 (a)End-quench testand cooling rate.(b) Hardenabilitycurves for fivedifferent steels, asobtained from theend-quench test.Small variations incomposition canchange the shape ofthese curves. Eachcurve is actually aband, and its exactdetermination isimportant in theheat treatment ofmetals, for bettercontrol ofproperties. Source:L. H. Van Vlack;Materials forEngineering.Addison-WesleyPublishing Co.,Inc., 1982.


Aluminum-Copper Phase Diagram

Figure 4.21 (a) Phase diagram for the aluminum-copper alloy system. (b) Various micro-structures obtained during the age-hardening process. Source: L. H. Van Vlack; Materials forEngineering. Addison-Wesley Publishing Co., Inc., 1982.


Age Hardening

Figure 4.22 The effect of agingtime and temperature on the yieldstress of 2014-T4 aluminum alloy.Note that, for each temperature,there is an optimal aging time formaximum strength.


Outline of Heat Treatment Processes forSurface Hardening

TABLE 4.1Process Metals hardened Element added to

surfaceProcedure General Characteristics Typical applications

Carburizing Low-carbon steel(0.2% C), alloysteels (0.08–0.2%C)

C Heat steel at 870–950 °C (1600–1750°F) in an atmosphere of carbonaceousgases (gas carburizing) or carbon-containing solids(pack carburizing). Then quench.

A hard, high-carbon surface isproduced. Hardness 55 to 65HRC. Case depth < 0.5–1.5 mm( < 0.020 to 0.060 in.). Somedistortion of part during heattreatment.

Gears, cams, shafts,bearings, piston pins,sprockets, clutch plates

Carbonitriding Low-carbon steel C and N Heat steel at 700–800 °C (1300–1600°F) in an atmosphere of carbonaceousgas and ammonia. Then quench in oil.

Surface hardness 55 to 62 HRC.Case depth 0.07 to 0.5 mm(0.003 to 0.020 in.). Lessdistortion than incarburizing.

Bolts, nuts, gears

Cyaniding Low-carbon steel(0.2% C), alloysteels (0.08–0.2%C)

C and N Heat steel at 760–845 °C (1400–1550°F) in a molten bath of solutions ofcyanide (e.g., 30% sodium cyanide) andother salts.

Surface hardness up to 65 HRC.Case depth 0.025 to 0.25 mm(0.001 to 0.010 in.). Somedistortion.

Bolts, nuts, screws, smallgears

Nitriding Steels (1% Al,1.5% Cr, 0.3%Mo), alloy steels(Cr, Mo), stainlesssteels, high-speedtool steels

N Heat steel at 500–600 °C (925–1100 °F)in an atmosphere of ammonia gas ormixtures of molten cyanide salts. Nofurther treatment.

Surface hardness up to 1100HV. Case depth 0.1 to 0.6 mm(0.005 to 0.030 in.) and 0.02 to0.07 mm (0.001to 0.003 in.) for high speedsteel.

Gears, shafts, sprockets,valves, cutters, boringbars, fuel-injection pumpparts

Boronizing Steels B Part is heated using boron-containinggas or solid in contact with part.

Extremely hard and wearresistant surface. Case depth0.025– 0.075 mm (0.001–0.003 in.).

Tool and die steels

Flame hardening Medium-carbonsteels, cast irons

None Surface is heated with an oxyacetylenetorch, then quenched with water spray orother quenching methods.

Surface hardness 50 to 60 HRC.Case depth 0.7 to 6 mm (0.030to 0.25 in.). Little distortion.

Gear and sprocket teeth,axles, crankshafts, pistonrods, lathe beds andcenters

Inductionhardening

Same as above None Metal part is placed in copper inductioncoils and is heated by high frequencycurrent, then quenched.

Same as above Same as above


Heat Treatment ProcessesFigure 4.23 Heat-treating temperature ranges forplain-carbon steels, as indicated on the iron-ironcarbide phase diagram. Source: ASMInternational.

Figure 4.24 Hardness of steels in the quenched andnormalized conditions, as a function of carbon content.


Properties of Oil-Quenched Steel

Figure 4.25 Mechanical properties ofoil-quenched 4340 steel, as a functionof tempering temperature. Source:Courtesy of LTV Steel Company


Induction Heating

Figure 4.26 Types of coils used in induction heating of various surfaces of parts.


CHAPTER 5

Ferrous Metals and Alloys: Production,General Properties, and Applications


Blast Furnace

Figure 5.1Schematicillustration of ablast furnace.Source: Courtesyof American Ironand Steel Institute.


Electric Furnaces

Figure 5.2 Schematic illustration of types of electric furnaces: (a) direct arc, (b) indirect arc, and (c) induction.


Basic-Oxygen Process

Figure 5.3 Schematicillustrations showing(a) charging, (b)melting, and (c)pouring of molten ironin a basic-oxygenprocess. Source:Inland Steel Company


ContinuousCasting

Figure 5.4 Thecontinuous-castingprocess for steel.Typically, the solidifiedmetal descends at a speedof 25 mm/s (1 in./s).Note that the platform isabout 20 m (65 ft) aboveground level. Source:Metalcaster's Referenceand Guide, AmericanFoundrymen's Society.


Typical Selection of Carbon and Alloy Steels forVarious Applications

TABLE 5.1Product Steel Product SteelAircraft forgings,

tubing, fittingsAutomobile bodiesAxlesBall bearings and racesBoltsCamshaftsChains (transmission)Coil springsConnecting rodsCrankshafts (forged)

4140, 8740

10101040, 4140521001035, 4042, 48151020, 10403135, 314040631040, 3141, 43401045, 1145, 3135, 3140

Differential gearsGears (car and truck)Landing gearLock washersNutsRailroad rails and wheelsSprings (coil)Springs (leaf)TubingWireWire (music)

40234027, 40324140, 4340, 87401060313010801095, 4063, 61501085, 4063, 9260, 615010401045, 10551085


Mechanical Properties of Selected Carbon andAlloy Steels in Various Conditions

TABLE 5.2 Typical Mechanical Properties of Selected Carbon and Alloy Steels in the Hot-Rolled,Normalized, and Annealed ConditionAISI Condition Ultimate

tensilestrength(MPa)

YieldStrength(MPa)

Elongation in50 mm (%)

Reduction ofarea (%)

Hardness(HB)

1020

1080

3140

4340

8620

As-rolledNormalizedAnnealedAs-rolled

NormalizedAnnealed

NormalizedAnnealed

NormalizedAnnealed

NormalizedAnnealed

448441393

1010965615891689

1279744632536

346330294586524375599422861472385357

363536121124192412222631

596766172045575036495962

143131111293293174262197363217183149


AISI Designation for High-Strength SheetSteel

TABLE 5.3Yield Strength Chemical

CompositionDeoxidation

Practice

psi x 103 MPa

35404550607080

100120140

240275310350415485550690830970

S = structural alloy

X = low alloy

W = weathering

D = dual phase

F = killed plus sulfide inclusion control

K = killed

O = nonkilled


Room-Temperature Mechanical Properties andApplications of Annealed Stainless Steels

TABLE 5.4 Room-Temperature Mechanical Properties and Typical Applications of Selected AnnealedStainless Steels

AISI(UNS)

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elongationin 50 mm

(%) Characteristics and typical applications303(S30300)

550–620 240–260 53–50 Screw machine products, shafts, valves, bolts,bushings, and nuts; aircraft fittings; bolts; nuts;rivets; screws; studs.

304(S30400)

565–620 240–290 60–55 Chemical and food processing equipment,brewing equipment, cryogenic vessels, gutters,downspouts, and flashings.

316(S31600)

550–590 210–290 60–55 High corrosion resistance and high creep strength.Chemical and pulp handling equipment,photographic equipment, brandy vats, fertilizerparts, ketchup cooking kettles, and yeast tubs.

410(S41000)

480–520 240–310 35–25 Machine parts, pump shafts, bolts, bushings, coalchutes, cutlery, tackle, hardware, jet engine parts,mining machinery, rifle barrels, screws, andvalves.

416(S41600)

480–520 275 30–20 Aircraft fittings, bolts, nuts, fire extinguisherinserts, rivets, and screws.


Basic Types of Tool and Die Steels

TABLE 5.5Type AISIHigh speed

Hot work

Cold work

Shock resisting

Mold steels

Special purpose

Water hardening

M (molybdenum base)T (tungsten base)H1 to H19 (chromium base)H20 to H39 (tungsten base)H40 to H59 (molybdenum base)D (high carbon, high chromium)A (medium alloy, air hardening)O (oil hardening)SP1 to P19 (low carbon)P20 to P39 (others)L (low alloy)F (carbon-tungsten)W


Processing and Service Characteristics ofCommon Tool and Die Steels

TABLE 5.6 Processing and Service Characteristics of Common Tool and Die Steels

AISIdesignation

Resistance todecarburization

Resistance tocracking

Approximatehardness(HRC) Machinability Toughness

Resistance tosoftening

Resistance towear

M2 Medium Medium 60–65 Medium Low Very high Very highT1 High High 60–65 Medium Low Very high Very highT5 Low Medium 60–65 Medium Low Highest Very highH11, 12, 13 Medium Highest 38–55 Medium to high Very high High MediumA2 Medium Highest 57–62 Medium Medium High HighA9 Medium Highest 35–56 Medium High High Medium to

highD2 Medium Highest 54–61 Low Low High High to very

highD3 Medium High 54–61 Low Low High Very highH21 Medium High 36–54 Medium High High Medium to

highH26 Medium High 43–58 Medium Medium Very high HighP20 High High 28–37 Medium to high High Low Low to

mediumP21 High Highest 30–40 Medium Medium Medium MediumW1, W2 Highest Medium 50–64 Highest High Low Low to

medium

Source: Adapted from Tool Steels, American Iron and Steel Institute, 1978.


CHAPTER 6

Nonferrous Metals and Alloys:Production, General Properties, and

Applications


Approximate Cost per Unit Volume for WroughtMetals and Plastics Relative to Carbon Steel

TABLE 6.1 Approximate Cost per Unit Volume for Wrought Metals and Plastics Relative toCost of Carbon SteelGoldSilverMolybdenum alloysNickelTitanium alloysCopper alloysZinc alloysStainless steels

60,000600200–2503520–405–61.5–3.52–9

Magnesium alloysAluminum alloysHigh-strength low-alloy steelsGray cast ironCarbon steelNylons, acetals, and silicon rubber

*

Other plastics and elastomers*

2–42–31.41.211.1–20.2–1

*As molding compounds.Note: Costs vary significantly with quantity of purchase, supply and demand, size and shape, and various other factors.


General Characteristics of Nonferrous Metalsand Alloys

TABLE 6.2Material CharacteristicsNonferrous alloys More expensive than steels and plastics; wide range of mechanical, physical, and

electrical properties; good corrosion resistance; high-temperature applications.Aluminum High strength-to-weight ratio; high thermal and electrical conductivity; good

corrosion resistance; good manufacturing properties.Magnesium Lightest metal; good strength-to-weight ratio.Copper High electrical and thermal conductivity; good corrosion resistance; good

manufacturing properties.Superalloys Good strength and resistance to corrosion at elevated temperatures; can be iron-,

cobalt-, and nickel-base.Titanium Highest strength-to-weight ratio of all metals; good strength and corrosion

resistance at high temperatures.Refractory metals Molybdenum, niobium (columbium), tungsten, and tantalum; high strength at

elevated temperatures.Precious metals Gold, silver, and platinum; generally good corrosion resistance.


Example of Alloy Usage

Figure 6.1 Cross-section of a jetengine (PW2037)showing variouscomponents and thealloys used inmanufacturingthem. Source:Courtesy of UnitedAircraft Pratt &Whitney.


Properties of Selected Aluminum Alloys atRoom Temperature

TABLE 6.3

Alloy (UNS) TemperUltimate tensilestrength (MPa)

Yield strength(MPa)

Elongationin 50 mm

(%)1100 (A91100)11002024 (A92024)20243003 (A93003)30035052 (A95052)50526061 (A96061)60617075 (A97075)7075

OH14

OT4O

H14O

H34OT6OT6

90125190470110150190260125310230570

3512075325401459021555275105500

35–459–2020–2219–2030–408–1625–3010–1425–3012–1716–17

11


Manufacturing Properties and Applications ofSelected Wrought Aluminum Alloys

TABLE 6.4

Characteristics*

AlloyCorrosionresistance Machinability Weldability Typical applications

1100 A C–D A Sheet metal work, spun hollow ware, tinstock

2024 C B–C B–C Truck wheels, screw machine products,aircraft structures

3003 A C–D A Cooking utensils, chemical equipment,pressure vessels, sheet metal work,builders’ hardware, storage tanks

5052 A C–D A Sheet metal work, hydraulic tubes, andappliances; bus, truck and marine uses

6061 B C–D A Heavy-duty structures where corrosionresistance is needed, truck and marinestructures, railroad cars, furniture,pipelines, bridge rail-ings, hydraulictubing

7075 C B–D D Aircraft and other structures, keys,hydraulic fittings

* A, excellent; D, poor.


All-Aluminum Automobile

Figure 6.2 (a) The Audi A8automobile which has an all-aluminum body structure. (b) Thealuminum body structure, showingvarious components made byextrusion, sheet forming, and castingprocesses. Source: Courtesy ofALCOA, Inc.


Properties and Typical Forms of SelectedWrought Magnesium Alloys

TABLE 6.5

Composition (%)Ultimatetensile Yield Elongation

Alloy Al Zn Mn Zr Conditionstrength(MPa)

strength(MPa)

in 50 mm(%) Typical forms

AZ31 B 3.0 1.0 0.2 F 260 200 15 ExtrusionsH24 290 220 15 Sheet and plates

AZ80A 8.5 0.5 0.2 T5 380 275 7 Extrusions andforgings

HK31A 3Th 0.7 H24 255 200 8 Sheet and platesZK60A 5.7 0.55 T5 365 300 11 Extrusions and

forgings


Properties and Typical Applications of SelectedWrought Copper and Brasses

TABLE 6.6

Type and UNSnumber

Nominalcomposition (%)

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elongationin 50 mm

(%) Typical applicationsElectrolytic tough pitch

copper (C11000)99.90 Cu, 0.04 O 220–450 70–365 55–4 Downspouts, gutters, roofing,

gaskets, auto radiators, busbars,nails, printing rolls, rivets

Red brass, 85%(C23000)

85.0 Cu, 15.0 Zn 270–725 70–435 55–3 Weather-stripping, conduits,sockets, fas-teners, fireextinguishers, condenser and heatexchanger tubing

Cartridge brass, 70%(C26000)

70.0 Cu, 30.0 Zn 300–900 75–450 66–3 Radiator cores and tanks, flashlightshells, lamp fixtures, fasteners,locks, hinges, ammunitioncomponents, plumbing accessories

Free-cutting brass(C36000)

61.5 Cu, 3.0 Pb,35.5 Zn

340–470 125–310 53–18 Gears, pinions, automatic high-speed screw machine parts

Naval brass(C46400 to C46700)

60.0 Cu, 39.25 Zn,0.75 Sn

380–610 170–455 50–17 Aircraft turnbuckle barrels, balls,bolts, marine hardware, propellershafts, rivets, valve stems,condenser plates


Properties and Typical Applications of SelectedWrought Bronzes

TABLE 6.7

Type and UNS numberNominal

composition (%)

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elongationin 50 mm

(%) Typical applicationsArchitectural bronze(C38500)

57.0 Cu, 3.0 Pb,40.0 Zn

415 (Asextruded)

140 30 Architectural extrusions, storefronts, thresholds, trim, butts,hinges

Phosphor bronze, 5% A(C51000)

95.0 Cu, 5.0 Sn,trace P

325–960 130–550 64–2 Bellows, clutch disks, cotter pins,diaphragms, fasteners, wirebrushes, chemical hardware, textilemachinery

Free-cutting phosphorbronze (C54400)

88.0 Cu, 4.0 Pb,4.0 Zn, 4.0 Sn

300–520 130–435 50–15 Bearings, bushings, gears, pinions,shafts, thrust washers, valve parts

Low silicon bronze, B(C65100)

98.5 Cu, 1.5 Si 275–655 100–475 55–11 Hydraulic pressure lines, bolts,marine hardware, electricalconduits, heat exchanger tubing

Nickel silver, 65–10(C74500)

65.0 Cu, 25.0 Zn,10.0 Ni

340–900 125–525 50–1 Rivets, screws, slide fasteners,hollow ware, nameplates


Properties and Typical Applications of SelectedNickel Alloys

TABLE 6.8 Properties and Typical Applications of Selected Nickel Alloys (All are Trade Names)

Type and UNS numberNominal

composition (%)

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elongationin 50 mm

(%) Typical applicationsNickel 200 (annealed) None 380–550 100–275 60–40 Chemical and food processing

industry, aerospace equipment,electronic parts

Duranickel 301 4.4 Al, 0.6 Ti 1300 900 28 Springs, plastics extrusion equipment,(age hardened) molds for glass,diaphragms

Monel R-405 (hotrolled)

30 Cu 525 230 35 Screw-machine products, water meterparts

Monel K-500 29 Cu, 3 Al 1050 750 30 Pump shafts, valve stems, springs (agehardened)

Inconel 600 (annealed) 15 Cr, 8 Fe 640 210 48 Gas turbine parts, heat-treatingequipment, electronic parts, nuclearreactors

Hastelloy C-4 (solution-treated and quenched)

16 Cr, 15 Mo 785 400 54 High temperature stability, resistanceto stress-corrosion cracking


Properties and Typical Applications of SelectedNickel-Base Superalloys at 870 °C

TABLE 6.9 Properties and Typical Applications of Selected Nickel-Base Superalloys at 870 °C(1600 °F) (All are Trade Names)

Alloy Condition

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elongationin 50 mm

(%) Typical applicationsAstroloy Wrought 770 690 25 Forgings for high temperatureHastelloy X Wrought 255 180 50 Jet engine sheet partsIN-100 Cast 885 695 6 Jet engine blades and wheelsIN-102 Wrought 215 200 110 Superheater and jet engine partsInconel 625 Wrought 285 275 125 Aircraft engines and structures,

chemical processing equipmentlnconel 718 Wrought 340 330 88 Jet engine and rocket partsMAR-M 200 Cast 840 760 4 Jet engine bladesMAR-M 432 Cast 730 605 8 Integrally cast turbine wheelsRené 41 Wrought 620 550 19 Jet engine partsUdimet 700 Wrought 690 635 27 Jet engine partsWaspaloy Wrought 525 515 35 Jet engine parts


Properties and Typical Applications of SelectedWrought Titanium Alloys

TABLE 6.10 Properties and Typical Applications of Selected Wrought Titanium Alloys at VariousTemperaturesNominalcompos-ition(%) UNS Condition

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elonga-tion (%)

Reduc-tion of

area (%)Temp.(°C)

Ultimatetensile

strength(MPa)

Yieldstrength(MPa)

Elonga-tion in50 mm

(%)

Reduc-tion ofarea Typical Applications

99.5 Ti R50250 Annealed 330 240 30 55 300 150 95 32 80 Airframes; chemical,desalination, andmarine parts; platetype heat exchangers

5 Al,2.5 Sn

R54520 Annealed 860 810 16 40 300 565 450 18 45 Aircraft enginecompressor blades andducting; steam turbineblades

6 Al,4V

R56400 Annealed 1000 925 14 30 300 725 650 14 35 Rocket motor cases;blades and disks foraircraft turbines andcompressors;structural forgings andfasteners; orthopedicimplants

425 670 570 18 40550 530 430 35 50

Solution +age

1175 1100 10 20 300 980 900 10 28

12 3522 45

13 V,11 Cr,3 Al

R58010 Solution +age

1275 1210 8 — 425 1100 830 12 — High strengthfasteners; aerospacecomponents;honeycomb panels


CHAPTER 7

Polymers: Structure, General Propertiesand Applications


Range of Mechanical Properties for VariousEngineering Plastics

TABLE 7.1

Material UTS (MPa) E (GPa)Elongation

(%)Poisson’sratio (ν)

ABSABS, reinforcedAcetalAcetal, reinforcedAcrylicCellulosicEpoxyEpoxy, reinforcedFluorocarbonNylonNylon, reinforcedPhenolicPolycarbonatePolycarbonate, reinforcedPolyesterPolyester, reinforcedPolyethylenePolypropylenePolypropylene, reinforcedPolystyrenePolyvinyl chloride

28–55100

55–70135

40–7510–48

35–14070–1400

7–4855–83

70–21028–7055–70

11055

110–1607–40

20–3540–10014–837–55

1.4–2.87.5

1.4–3.510

1.4–3.50.4–1.43.5–1721–520.7–2

1.4–2.82–10

2.8–212.5–3

62

8.3–120.1–1.40.7–1.23.5–61.4–4

0.014–4

75–5—

75–25—

50–5100–510–14–2

300–100200–60

10–12–0

125–106–4

300–53–1

1000–15500–10

4–260–1

450–40

—0.35—

0.35–0.40————

0.46–0.480.32–0.40

——

0.38—

0.38—

0.46——

0.35—


Chapter 7 Outline

Figure 7.1 Outline of the topics described in Chapter 7


Structure ofPolymer

Molecules

Figure 7.2 Basic structure of polymer molecules: (a) ethylene molecule; (b)polyethylene, a linear chain of many ethylene molecules; © molecular structureof various polymers. These are examples of the basic building blocks forplastics


Molecular Weight and Degree of Polymerization

Figure 7.3 Effect of molecular weightand degree of polymerization on thestrength and viscosity of polymers.


Polymer Chains

Figure 7.4 Schematicillustration of polymer chains.(a) Linear structure--thermoplastics such asacrylics, nylons, polyethylene,and polyvinyl chloride havelinear structures. (b) Branchedstructure, such as inpolyethylene. (c) Cross-linkedstructure--many rubbers orelastomers have this structure,and the vulcanization of rubberproduces this structure. (d)Network structure, which isbasically highly cross-linked--examples are thermosettingplastics, such as epoxies andphenolics.


Polymer Behavior

Figure 7.5 Behavior of polymers as a function of temperature and (a) degree of crystallinity and (b)cross-linking. The combined elastic and viscous behavior of polymers is known as viscoelasticity.


Crystallinity

Figure 7.6 Amorphousand crystalline regions ina polymer. The crystallineregion (crystallite) has anorderly arrangement ofmolecules. The higher thecrystallinity, the harder,stiffer, and less ductile thepolymer.


Specific Volume as a Function of Temperature

Figure 7.7 Specific volume of polymersas a function of temperature. Amorphouspolymers, such as acrylic andpolycarbonate, have a glass-transitiontemperature, Tg, but do not have a specificmelting point, Tm. Partly crystallinepolymers, such as polyethylene andnylons, contract sharply while passingthrough their melting temperatures duringcooling.


Glass-Transition and Melting Temperatures ofSome Polymers

TABLE 7.2Material Tg (°C) Tm (°C)Nylon 6,6PolycarbonatePolyesterPolyethylene

High densityLow density

PolymethylmethacrylatePolypropylenePolystyrenePolytetrafluoroethylenePolyvinyl chlorideRubber

5715073

–90–110105–14100–9087–73

265265265

137115—176239327212—


Behavior of Plastics

Figure 7.8 General terminology describingthe behavior of three types of plastics. PTFE(polytetrafluoroethylene) has Teflon as itstrade name. Source: R. L. E. Brown.


Temperature Effects

Figure 7.9 Effect of temperature on the stress-straincurve for cellulose acetate, a thermoplastic. Note thelarge drop in strength and the large increase inductility with a relatively small increase intemperature. Source: After T. S. Carswell and H. K.Nason. Figure 7.10 Effect of temperature on the impact

strength of various plastics. Small changes intemperature can have a significant effect on impactstrength. Source: P. C. Powell.


Elongation

(a) (b) Figure 7.11 (a) Load-elongation curve forpolycarbonate, athermoplastic. Source: R. P.Kambour and R. E.Robertson. (b) High-densitypolyethylene tensile-testspecimen, showing uniformelongation (the long, narrowregion in the specimen).


General Recommendations for Plastic Products

TABLE 7.3Design requirement Applications PlasticsMechanical strength Gears, cams, rollers, valves, fan

blades, impellers, pistonsAcetal, nylon, phenolic,polycarbonate

Functional and decorative Handles, knobs, camera andbattery cases, trim moldings, pipefittings

ABS, acrylic, cellulosic,phenolic, polyethylene,polypropylene, polystyrene,polyvinyl chloride

Housings and hollow shapes Power tools, pumps, housings,sport helmets, telephone cases

ABS, cellulosic, phenolic,polycarbonate, polyethylene,polypropylene, polystyrene

Functional and transparent Lenses, goggles, safety glazing,signs, food-processingequipment, laboratory hardware

Acrylic, polycarbonate,polystyrene, polysulfone

Wear resistance Gears, wear strips and liners,bearings, bushings, roller-skatewheels

Acetal, nylon, phenolic,polyimide, polyurethane,ultrahigh molecular weightpolyethylene


Load-Elongation Curve for Rubber

Figure 7.12 Typical load-elongationcurve for rubbers. The clockwise lop,indicating the loading and theunloading paths, displays the hysteresisloss. Hysteresis gives rubbers thecapacity to dissipate energy, dampvibraion, and absorb shock loading, asis necessary in automobile tires and invibration dampers placed undermachinery.


CHAPTER 8

Ceramics, Graphite, and Diamond:Structure, General Properties, and

Applications


Examples of Ceramics

(a) (b)

Figure 8.1 A variety of ceramic components. (a) High-strength alumina for high-temperatureapplications. (b) Gas-turbine rotors made of silicon nitride. Source: Wesgo Div., GTE.


Types andGeneral

Characteristicsof Ceramics

TABLE 8.1Type General CharacteristicsOxide ceramics

Alumina High hardness, moderate strength; most widely used ceramic;cutting tools, abrasives, electrical and thermal insulation.

Zirconia High strength and toughness; thermal expansion close to cast iron ;suitable for heat engine components.

CarbidesTungsten carbide Hardness, strength, and wear resistance depend on cobalt binder

content; commonly used for dies and cutting tools.Titanium carbide Not as tough as tungsten carbide; has nickel and molybdenum as

the binder; used as cutting tools.Silicon carbide High-temperature strength and wear resistance ; used for heat

engines and as abrasives.Nitrides

Cubic boron nitride Second-hardest substance known, after diamond; used as abrasivesand cutting tools.

Titanium nitride Gold in color; used as coatings because of low frictionalcharacteristics.

Silicon nitride High resistance to creep and thermal shock; used in heat engines.Sialon Consists of silicon nitrides and other oxides and carbides; used as

cutting tools.Cermets Consist of oxides, carbides, and nitrides; used in high-temperature

applications.Silica High temperature resistance; quartz exhibits piezoelectric effect;

silicates containing various oxides are used in high-temperaturenonstructural applications.

Glasses Contain at least 50 percent silica; amorphous structures; severaltypes available with a range of mechanical and physical properties.

Glass ceramics Have a high crystalline component to their structure ; good thermal-shock resistance and strong.

Graphite Crystalline form of carbon; high electrical and thermalconductivity; good thermal shock resistance.

Diamond Hardest substance known; available as single crystal orpolycrystalline form; used as cutting tools and abrasives and as diesfor fine wire drawing.


Properties of Various Ceramics at RoomTemperature

TABLE 8.2

Material Symbol

Transverserupturestrength(MPa)

Compressivestrength(MPa)

Elasticmodulus

(GPa)Hardness

(HK)Poisson’sratio (ν)

Density(kg/m3)

Aluminumoxide

Al2O3 140–240 1000–2900 310–410 2000–3000 0.26 4000–4500

Cubic boronnitride

CBN 725 7000 850 4000–5000 — 3480

Diamond — 1400 7000 830–1000 7000–8000 — 3500Silica, fused SiO2 — 1300 70 550 0.25 —Siliconcarbide

SiC 100–750 700–3500 240–480 2100–3000 0.14 3100

Siliconnitride

Si3 N4 480–600 — 300–310 2000–2500 0.24 3300

Titaniumcarbide

TiC 1400–1900 3100–3850 310–410 1800–3200 — 5500–5800

Tungstencarbide

WC 1030–2600 4100–5900 520–700 1800–2400 — 10,000–15,000

Partiallystabilizedzirconia

PSZ 620 — 200 1100 0.30 5800

Note: These properties vary widely depending on the condition of the material.


Properties of Various Glasses

TABLE 8.3Soda-lime

glassLead glass Borosilicate

glass96 Percent

silicaFusedsilica

Density High Highest Medium Low LowestStrength Low Low Moderate High HighestResistance to thermal

shockLow Low Good Better Best

Electrical resistivity Moderate Best Good Good GoodHot workability Good Best Fair Poor PoorestHeat treatability Good Good Poor None NoneChemical resistance Poor Fair Good Better BestImpact-abrasion

resistanceFair Poor Good Good Best

Ultraviolet-lighttransmission

Poor Poor Fair Good Good

Relative cost Lowest Low Medium High Highest


Graphite Components

Figure 8.2 Variousengineeringcomponents made ofgraphite. Source: PocoGraphite, Inc., a UnocalCo.


CHAPTER 9

Composite Materials: Structure, GeneralProperties, and Applications


Application of Advanced Composite Materials

Figure 9.1Application ofadvancedcompositematerials inBoeing 757-200commercialaircraft. Source:BoeingCommercialAirplaneCompany.


Methods of Reinforcing Plastics

Figure 9.2 Schematicillustration of methodsof reinforcing plastics(matrix) with (a)particles, and (b) shortor long fibers orflakes. The four layersof continuous fibers inillustration (c) areassembled into alaminate structure.


Types and General Characteristics ofComposite Materials

TABLE 9.1Material CharacteristicsFibers Glass High strength, low stiffness, high density; lowest cost; E (calcium aluminoborosilicate) and S

(magnesia-aluminosilicate) types commonly used. Graphite Available as high-modulus or high-strength; low cost; less dense than glass. Boron High strength and stiffness; highest density; highest cost; has tungsten filament at its center. Aramids (Kevlar) Highest strength-to-weight ratio of all fibers; high cost. Other fibers Nylon, silicon carbide, silicon nitride, aluminum oxide, boron carbide, boron nitride, tantalum

carbide, steel, tungsten, molybdenum.Matrix materials Thermosets Epoxy and polyester, with the former most commonly used; others are phenolics,

fluorocarbons, polyethersulfone, silicon, and polyimides. Thermoplastics Polyetheretherketone; tougher than thermosets but lower resistance to temperature. Metals Aluminum, aluminum-lithium, magnesium, and titanium; fibers are graphite, aluminum oxide,

silicon carbide, and boron. Ceramics Silicon carbide, silicon nitride, aluminum oxide, and mullite; fibers are various ceramics.


Strength and Stiffness of Reinforced Plastics

Figure 9.3 Specific tensile strength (tensile strength-to-density ratio) and specific tensile modulus(modulus of elasticity-to-density ratio) for various fibers used in reinforced plastics. Note the widerange of specific strengths and stiffnesses available.


Typical Properties of Reinforcing Fibers

TABLE 9.2

Type

Tensilestrength(MPa)

Elasticmodulus

(GPa)Density( kg/m

3) Relative cost

Boron 3500 380 2600 HighestCarbon High strength 3000 275 1900 Low High modulus 2000 415 1900 LowGlass E type 3500 73 2480 Lowest S type 4600 85 2540 LowestKevlar 29 2800 62 1440 High 49 2800 117 1440 HighNote: These properties vary significantly depending on the material and method of preparation.


Fiber Reinforcing

Figure 9.4 (a) Cross-section of a tennis racket, showing graphite and aramid (Kevlar) reinforcing fibers. Source:J. Dvorak, Mercury Marine Corporation, and F. Garrett, Wilson Sporting Goods Co. (b) Cross-section of boronfiber-reinforced composite material.


Effect of Fiber Type on Fiber-Reinforced Nylon

Figure 9.5 The effectof type of fiber onvarious properties offiber-reinforced nylon(6,6). Source: NASA.


Fracture Surfaces of Fiber-Reinforced EpoxyComposites

(a) (b)

Figure 9.6 (a) Fracture surface of glass-fiber reinforced epoxy composite. The fibers are10 µm (400 µin.) in diameter and have random orientation. (b) Fracture surface of agraphite-fiber reinforced epoxy composite. The fibers, 9 µm-11 µm in diameter, are inbundles and are all aligned in the same direction. Source: L. J. Broutman.


Tensile Strength of Glass-Reinforced Polyester

Figure 9.7 The tensile strengthof glass-reinforced polyester as afunction of fiber content andfiber direction in the matrix.Source: R. M. Ogorkiewicz, TheEngineering Properties ofPlastics. Oxford: OxfordUniversity Press, 1977.


Example of Advanced Materials Construction

Figure 9.8 Cross-section of acomposite sailboard, an exampleof advanced materialsconstruction. Source: K.Easterling, Tomorrow’s Materials(2d ed.), p. 133. Institute ofMetals, 1990.


Metal-Matrix Composite Materials andApplications

TABLE 9.3Fiber Matrix ApplicationsGraphite Aluminum

MagnesiumLeadCopper

Satellite, missile, and helicopter structuresSpace and satellite structuresStorage-battery platesElectrical contacts and bearings

Boron AluminumMagnesiumTitanium

Compressor blades and structural supportsAntenna structuresJet-engine fan blades

Alumina AluminumLeadMagnesium

Superconductor restraints in fission power reactorsStorage-battery platesHelicopter transmission structures

Silicon carbide Aluminum, titaniumSuperalloy (cobalt-base)

High-temperature structuresHigh-temperature engine components

Molybdenum, tungsten Superalloy High-temperature engine components


CHAPTER 10

Fundamentals of Metal-Casting


Cast Structures of Metals

Figure 10.1 Schematic illustration ofthree cast structures of metalssolidified in a square mold: (a) puremetals; (b) solid-solution alloys; and(c) structure obtained by usingnucleating agents. Source: G. W.Form, J. F. Wallace, J. L. Walker, andA. Cibula.


Preferred Texture Development

Figure 10.2 Development of a preferred texture at a cool mold wall. Note that onlyfavorably oriented grains grow away from the surface of the mold.


Alloy Solidification

Figure 10.3 Schematicillustration of alloysolidification andtemperaturedistribution in thesolidifying metal.Note the formation ofdendrites in the mushyzone.


Solidification Patterns

Figure 10.4 (a) Solidification patterns for gray cast iron in a 180-mm (7-in.) square casting. Note thatafter 11 min. of cooling, dendrites reach each other, but the casting is still mushy throughout. It takesabout two hours for this casting to solidify completely. (b) Solidification of carbon steels in sand andchill (metal) molds. Note the difference in solidification patterns as the carbon content increases.Source: H. F. Bishop and W. S. Pellini.


Cast Structures

Figure 10.5Schematicillustration of threebasic types of caststructures: (a)columnar dendritic;(b) equiaxeddendritic; and (c)equiaxednondendritic.Source: D. Apelian.

Figure 10.6 Schematic illustration of cast structuresin (a) plane front, single phase, and (b) plane front,two phase. Source: D. Apelian.


Riser-Gated Casting

Figure 10.7 Schematic illustrationof a typical riser-gated casting.Risers serve as reservoirs,supplying molten metal to thecasting as it shrinks duringsolidification. See also Fig. 11.4Source: American Foundrymen’sSociety.


Fluidity Test

Figure 10.8 A test method for fluidity usinga spiral mold. The fluidity index is the lengthof the solidified metal in the spiral passage.The greater the length of the solidified metal,the greater is its fluidity.


Temperature Distribution

Figure 10.9 Temperaturedistribution at the interface of themold wall and the liquid metalduring solidification of metals incasting.


Solidification Time

Figure 10.10 Solidified skin on asteel casting. The remainingmolten metal is poured out at thetimes indicated in the figure.Hollow ornamental and decorativeobjects are made by a processcalled slush casting, which is basedon this principle. Source: H. F.Taylor, J. Wulff, and M. C.Flemings.


Solidification Contraction for Various CastMetals

TABLE 10.1

Metal or alloy

Volumetricsolidification

contraction (%) Metal or alloy

Volumetricsolidification

contraction (%)Aluminum 6.6 70%Cu–30%Zn 4.5Al–4.5%Cu 6.3 90%Cu–10%Al 4Al–12%Si 3.8 Gray iron Expansion to 2.5Carbon steel 2.5–3 Magnesium 4.21% carbon steel 4 White iron 4–5.5Copper 4.9 Zinc 6.5Source: After R. A. Flinn.


Hot Tears

Figure 10.11 Examples of hot tears in castings. These defects occur becausethe casting cannot shrink freely during cooling, owing to constraints invarious portions of the molds and cores. Exothermic (heat-producing)compounds may be used (as exothermic padding) to control cooling at criticalsections to avoid hot tearing.


Casting DefectsFigure 10.12 Examples of common defects in castings. These defects can be minimized or eliminated byproper design and preparation of molds and control of pouring procedures. Source: J. Datsko.


Internal and External Chills

Figure 10.13Various types of(a) internal and(b) external chills(dark areas atcorners), used incastings toeliminate porositycaused byshrinkage. Chillsare placed inregions wherethere is a largervolume of metals,as shown in (c).


Solubility of Hydrogen in Aluminum

Figure 10.14 Solubility of hydrogen inaluminum. Note the sharp decrease insolubility as the molten metal begins tosolidify.

manufacturing science part 1

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