the structure of metals

Kalpakjian, Manufacturing Processes for Engineering Materials © 1997 Addison Wesley Page 3-1

CHAPTER 3

The Structure of Metals(금속의구조와가공특성)


Chapter 1 Outline

Figure 3.1 An outline of the topics described in Chapter 3

Kalpakjian, Manufacturing Processes for Engineering Materials © 1997 Addison Wesley -3

- It is applied to all materials including metal(금속뿐만아니라모든재료의구조에적용됨)

- Crystal structure: Bravis lattice – 14 systems -> Too many?- Crystal direction and plane: Miller index

Crystal structure


Body-Centered Cubic Crystal Structure

Figure 3.2(a) The body-centered cubic (bcc) crystal structure: (a) hard-ball model; (b) unit cell; and (c) single crystal 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 3.2(b) The face-centered cubic (fcc) crystal structure: (a) hard-ball model; (b) unit cell; and (c) single crystal 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 3.2(c) The hexagonal close-packed (hcp) crystal structure: (a) unit cell; and (b) single crystal with many unit cells. Source: W. G. Moffatt, et al., The Structure and Properties of Materials, Vol. 1, John Wiley & Sons, 1976.


Miller indices (1)

• [abc] in a cubic crystal is a direction vector• (abc) is a plane passing through (1/a, 1/b, 1/c),

and is perpendicular to the [abc] vector for cubic crystal

• (…)/[…] indicate a specific plane/direction• {…}/<…> indicate equivalent planes/directions (family)

- <100>: [100], [ 00], [010], [0 0], [001], [00 ] in cubic crystal1 1 1


Miller indices (2)

ab

c[abc]

[100]

[010]

[001]

1/a

1/b

1/c (abc)

PlaneDirection

[100]

[010]

[001]

(110)(111)


Slip and Twinning

Figure 3.3 Permanent deformation (also called plastic deformation) of a single crystal subjected to a shear stress: (a) structure before deformation; and (b) permanent deformation by slip. The size of the b/a ratio influences the magnitude of the shear stress required to cause slip.

Figure 3.4 (a) Permanent deformation of a single crystal under a tensile load. Note that the slip planes tend to align themselves in the direction of the pulling force. This behaviour can be simulated using a deck of cards with a rubber band around them. (b) Twinning in a single crystal in tension. Usually hcp metals.


Slip Lines and Slip Bands

Figure 3.6 Schematic illustration of slip lines and slip bands in a single crystal (grain) subjected to a shear stress. A slip band consists of a number of slip planes. The crystal at the center of the upper illustration is an individual grain surrounded by other grains.

(a) BCC: 48 slip systems, titanium, molybdenum, and tungsten, good strength and moderate ductility(b) FCC: 12 slip systems, aluminum, copper, gold, and silver, moderate strength and good ductility(c) HCP: 3 slip systems, beryllium, magnesium, and zinc, brittle at room temp.


Defects (good or bad?)

- Materials are not perfect (Si wafer? Single crystal?)- Point, Line, Surface, Volume defects- Useful for deformation, alloying and heat treatment

Defects


Point Defects in a Single-Crystal Lattice

Figure 3.8 Schematic illustration of types of defects in a single-crystal lattice: self-interstitial, vacancy, interstitial, and substitutional.


Line Defects: Edge and Screw Dislocations

Figure 3.9 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 for Engineering, 4th ed., 1980.


Movement of an Edge Dislocation

Figure 3.10 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 by theory.


DISLOCATION DENSITY

Dislocation density: total dislocation length per unit volume of material …or the number of dislocations that intersect a unit area of a random sectionThe dislocation density typically determines the strength of a material

Metals (carefully solidified): 103 mm-2

Metals (heavily deformed): 109-1010 mm-2

Metals (heat treated): 105-106 mm-2

Ceramics: 102-104 mm-2

Single crystal silicon for ICs: 0.1-1 mm-2


Solidification Grain boundary: Surface defectsFigure 3.11 Schematic illustration of the stages during solidification of molten metal; each small square represents a unit cell. (a) Nucleation of crystals at random sites in the molten metal; note that the crystallographic orientation of each site is different. (b) and (c) Growth of crystals as solidification continues. (d) Solidified metal, showing individual grains and grain boundaries; note the different angles at which neighboringgrains meet each other. Source: W. Rosenhain.


Review: Phase diagram of Fe-C

- Eutectoid (0.77%C)- Ferrite (BCC, α-Fe)- Austenite (FCC, γ-Fe)- Cementite (?, Fe3C)- Martensite (BCT):

Metastable phase by quenchingTherefore, it is not shown in the phase diagram!


Phase diagram of Fe-C

- Pearlite: microstructure not phaseAlternating layers of ferrite(soft, ductile)and cementite(hard, brittle)Improve mechanical property (strong and ductile)Why does such microstructure occur? Diffusion!!

- Martensite: metastable phase (Quenching is needed to form martensite)Not shown in phase diagram because it does not occur under equilibrium conditionExtremely brittle, cannot be used (carbon cannot be diffused by quenching)After heat treatment (tempering), mechanical properties are enhanced.


Grain Sizes: Hall-Petch Eqn.

TABLE 3.1 ASTM No. Grains/mm2 Grains/mm3 –3 –2 –1 0 1 2 3 4 5 6 7 8 9 10 11 12

1 2 4 8 16 32 64 128 256 512

1,024 2,048 4,096 8,200 16,400 32,800

0.7 2

5.6 16 45 128 360

1,020 2,900 8,200 23,000 65,000 185,000 520,000

1,500,000 4,200,000

21−+= dk yoy σσ


STRENGTHENING MECHANISMS

- Macroscopic plastic deformation corresponds to the motion of large numbers of dislocations.

-The ability of a metal to plastically deform depends on the ability of dislocations to move (Think of slip system).

- Therefore, all strengthening techniques rely on restricting or hindering dislocation motion -> How?

Four strengthening mechanisms

(1) Grain size reduction(2) Work hardening with cold working(3) Solid-solution strengthening(4) Precipitation strengthening/hardening


Defects - point, line, surface, volume defects- useful for deformation, alloying as well as HEAT TREATMENT

Point defect

Review: Defects

Line defectDislocation & Slip

Surface defect Grain Boundary & Slip


• Grain boundaries act as barriers to slip.

- grain boundary region:disordered, so discontinuity inslip planes

- dislocation has to change directions at grain boundary

• Barrier "strength” increases with misorientation.

• Smaller grain size: more barriers to slip.

• Hall-Petch Equation:

grain boundary

slip plane

grain Agra

in B

σyield = σo +k yd−1/2

GRAIN SIZE REDUCTION

d: average grain length


• Room temperature deformation.• Common forming operations change the cross sectional area:

Ao Ad

force

dieblank

force

-Forging -Rolling

-Extrusion-Drawing

tensile force

AoAddie

dieram billet

container

containerforce

die holder

die

Ao

Adextrusion

roll

AoAd

roll

Work hardening by cold work

• Dislocations entangle with one another, and are piled up at the grain boundary during cold work.

• Dislocation motion becomes more difficult.


• Impurity atoms distort the lattice & generate stress.• Stress then produces a barrier to dislocation motion.• Alloys are stronger than pure metals -> Alloying

• Smaller substitutional impurity • Larger substitutional impurity

SOLID SOLUTION STRENGTHENING

C

D

A

B


• Hard precipitates are difficult to shear.Ex: Ceramics in metals (SiC in iron or Aluminum).

• How to make precipitates? Heat treatment

• Uniformly distributed small precipitates are more effectivesimilar to grain size reduction.

σy ~

1S

PRECIPITATION HARDENING

1.5µm

Aluminum is strengthened with precipitates

S=?


Precipitation Hardening

- Heat treatment of Martensite for Ferrous and Aluminum alloyto enhance ductility or strength

- Quenching -> Aging- Disperse small precipitates uniformly- Overaging -> Precipitates become larger with time… Why? Good?

duralumin (두랄루민)A1- 4％Cu - etc


Preferred Orientation

Figure 3.14 Plastic deformation of idealized (equiaxed) grains in a specimen subjected to compression (such as occurs in the rolling or forging of metals): (a) before deformation; and (b) after deformation. Note the alignment of grain boundaries along a horizontal direction; this effect is known as preferred orientation.

Anisotropy & Residual stress due to deformationTo relieve it, use heat treatment such as annealing


Anisotropy

Figure 3.15 (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 with respect 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 3.16 Schematic illustration of the effects of recovery, recrystallization, and grain growth on mechanical properties and on the shape and size of grains. Note the formation of small new grains during recrystallization. Source: G. Sachs.

Effect of heat treatment:- Recovery, Recrystallization,

Grain Growth- Why grain grows larger at high

Temp.? Grain boundary has higher surface energy-> minimize energy at high

temperature- Strength, Hardness vs. Ductility


ten

sile

str

en

gth

(M

Pa

)

du

cti

lity

(%E

L)

Annealing Temperature ( )캜

300

400

500

600 60

50

40

30

20Recovery

Recrystallization

Grain Growth

ductility

tensile strength300 700500100

Annealing Processes

Note:You cannot get both strength

and ductility.Thus, you should choose

depending on applications.


Diagrams for Heat Treatment - TTT(Time-Temperature-Transformatio) and CCT(Continuous Cooling Transformation) diagrams

: Time is included… So, composition is fixed.

TTT diagram

CCT diagram


• Dislocations motion correlates to plastic deformation.

• Strength is increased by making dislocation motion difficult.

• In order to increase strength,- grain size reduction- work-hardening with cold work - solid solution strengthening- precipitate strengthening

SUMMARY


Homologous Temperature Ranges for Various Processes

TABLE 3.2 Process T/Tm Cold working Warm working Hot working

< 0.3 0.3 to 0.5 > 0.6


Rough Surface

Figure 3.19 Rough surface developed on an aluminum compression

specimen by the presence of a high-viscosity lubricant and high

compression speed. The coarser the grain size, the rougher the surface. Source: A. Mulc and S. Kalpakjian.


Failures of Materials and Fractures in Tension

Figure 3.20 Schematic illustration of types of failures in materials: (a) necking and fracture of ductile materials; (b) Buckling of ductile materials under a compressive load; (c) fracture of brittle materials in compression; (d) cracking on the barreled surface of ductile materials in compression.

Figure 3.21 Schematic illustration of the types of fracture in tension: (a) brittle fracture in polycrystalline metals; (b) shear fracture in ductile single crystals--see also Fig. 1.6a; (c) ductile cup-and-cone fracture in polycrystalline metals; (d) complete ductile fracture in polycrystalline metals, with 100% reduction of area.


Ductile Fracture

Figure 3.22 Surface of ductile fracture in low-carbon steel, showing dimples. Fracture is usually initiated at impurities, inclusions, or preexisting voids (microporosity) in the metal. Source: K.-H. Habig and D. Klaffke. Photo by BAM Berlin/Germany.

Shear stress is a maximum.


Fracture of a Tensile-Test Specimen

Figure 3.24 Sequence of events in necking and fracture of a tensile-test specimen: (a) early stage of necking; (b) small voids begin to form within the necked region; (c) voids coalesce, producing an internal crack; (d) the rest of the cross-section begins to fail at the periphery, by shearing; (e) the final fracture surfaces, known as cup- (top fracture surface) and cone- (bottom surface) fracture.


Deformation of Soft and Hard Inclusions

Figure 3.26 Schematic illustration of the deformation of soft and hard inclusions and of their effect on void formation in plastic deformation. Note that, because they do not comply with the overall deformation of the ductile matrix, hard inclusions can cause internal voids.


Transition Temperature

Figure 3.27 Schematic illustration of transition temperature in metals.

High rates of deformation, abrupt changes in shape, and surface notches raise the transition temperature. BCC and HCP, rarely by FCC.


Brittle Fracture Surface

Figure 3.29 Fracture surface of steel that has failed in a brittle manner. The fracture path is transgranular (through the grains). Magnification: 200X. Source: Courtesy of B. J. Schulze and S. L. Meiley and Packer Engineering Associates, Inc.

Fracture takes place along a crystallographic plane, called a cleavage plane, on which the normal tensile stress is a maximum.


Intergranular Fracture

Figure 3.30 Intergranular fracture, at two different magnifications. Grains and grain boundaries are clearly visible in this micrograph. Te fracture path is along the grain boundaries. Magnification: left, 100X; right, 500X. Source: Courtesy of B. J. Schulze and S. L. Meiley and Packer Engineering Associates, Inc.

The crack propagates along the grain boundary compared to the intragranular fracture where crack propagates through the grain.


Fatigue-Fracture Surface

Figure 3.32 Typical fatigue-fracture surface on metals, showing beach marks. Magnification: left, 500X; right, 1000X. Source: Courtesy of B. J. Schulze and S. L. Meiley and Packer Engineering Associates, Inc.

Minute external or internal cracks develop at flaws or defects in the material, which then propagate and eventually lead to total failure.


Reduction in Fatigue Strength

Figure 3.33 Reductions in the fatigue strength of cast steels subjected to various surface-finishing operations. Note that the reduction becomes greater as the surface roughness and the strength of the steel increase. Source: M. R. Mitchell.


Physical Properties of Selected Materials at Room Temperature

TABLE 3.3 Physical Properties of Selected Materials at Room Temperature Metal Density

(kg/m3)

Melting Point (°C)

Specific heat (J/kg K)

Thermal conductivity (W/m K)

Aluminum Aluminum alloys Beryllium Columbium (niobium) Copper Copper alloys Iron Steels Lead Lead alloys Magnesium Magnesium alloys Molybdenum alloys Nickel Nickel alloys Tantalum alloys Titanium Titanium alloys Tungsten Zinc Zinc alloys

2700 2630–2820

1854 8580 8970

7470–8940 7860

6920–9130 11,350

8850–11,350 1745

1770–1780 10,210 8910

7750–8850 16,600 4510

4430–4700 19,290 7140

6640–7200

660 476–654

1278 2468 1082

885–1260 1537

1371–1532 327

182–326 650

610–621 2610 1453

1110–1454 2996 1668

1549–1649 3410 419

386–525

900 880–920

1884 272 385

377–435 460

448–502 130

126–188 1025 1046 276 440

381–544 142 519

502–544 138 385 402

222 121–239

146 52

393 29–234

74 15–52

35 24–46

154 75–138

142 92

12–63 54 17

8–12 166 113

105–113

Nonmetallic Ceramics Glasses Graphite Plastics Wood

2300–5500 2400–2700 1900–2200 900–2000 400–700

— 580–1540

— 110–330

—

750–950 500–850

840 1000–2000 2400–2800

10–17 0.6–1.7

5–10 0.1–0.4 0.1–0.4


Room-Temperature Mechanical Properties and Applications of Annealed Stainless Steels

TABLE 3.4 Room-Temperature Mechanical Properties and Typical Applications of Selected Annealed Stainless Steels AISI (UNS)

Ultimate tensile

strength (MPa)

Yield

strength (MPa)

Elongation in 50 mm

(%)

Characteristics and typical applications 303 (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, fertilizer parts, ketchup cooking kettles, and yeast tubs.

410 (S41000)

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

416 (S41600)

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


Basic Types of Tool and Die Steels

TABLE 3.5 Type AISI High 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) S P1 to P19 (low carbon) P20 to P39 (others) L (low alloy) F (carbon-tungsten) W


Processing and Service Characteristics of Common Tool and Die Steels

TABLE 3.6 Processing and Service Characteristics of Common Tool and Die Steels AISI designation

Resistance to

decarburization

Resistance to

cracking

Approximate hardness (HRC)

Machinability

Toughness

Resistance to

softening

Resistance to

wear M2 Medium Medium 60–65 Medium Low Very high Very high T1 High High 60–65 Medium Low Very high Very high T5 Low Medium 60–65 Medium Low Highest Very high H11, 12, 13 Medium Highest 38–55 Medium to high Very high High Medium A2 Medium Highest 57–62 Medium Medium High High A9 Medium Highest 35–56 Medium High High Medium to

high D2 Medium Highest 54–61 Low Low High High to very

high D3 Medium High 54–61 Low Low High Very high H21 Medium High 36–54 Medium High High Medium to

high H26 Medium High 43–58 Medium Medium Very high High P20 High High 28–37 Medium to high High Low Low to

medium P21 High Highest 30–40 Medium Medium Medium Medium W1, W2 Highest Medium 50–64 Highest High Low Low to

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


General Characteristics of Nonferrous Metals and Alloys

TABLE 3.7 Material Characteristics Nonferrous 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 3.34 Cross-section of a jet engine (PW2037) showing various components and the alloys used in manufacturing them. Source: Courtesy of United Aircraft Pratt & Whitney.


Properties of Selected Aluminum Alloys at Room Temperature

TABLE 3.8

Alloy (UNS) Temper Ultimate tensile strength (MPa)

Yield strength (MPa)

Elongation in 50 mm

(%) 1100 (A91100) 1100 2024 (A92024) 2024 3003 (A93003) 3003 5052 (A95052) 5052 6061 (A96061) 6061 7075 (A97075) 7075

O H14

O T4 O

H14 O

H34 O T6 O T6

90 125 190 470 110 150 190 260 125 310 230 570

35 120 75 325 40 145 90 215 55 275 105 500

35–45 9–20 20–22 19–20 30–40 8–16 25–30 10–14 25–30 12–17 16–17

11


Manufacturing Properties and Applications of Selected Wrought Aluminum Alloys

TABLE 3.9 Characteristics*

Alloy Corrosion resistance

Machinability

Weldability Typical applications

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

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, and appliances; bus, truck and marine uses

6061 B C–D A Heavy-duty structures where corrosion resistance is needed, truck and marine structures, railroad cars, furniture, pipelines, bridge rail-ings, hydraulic tubing

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

* A, excellent; D, poor.


All-Aluminum Automobile

Figure 3.35 (a) The Audi A8 automobile which has an all-aluminum body structure. (b) The aluminum body structure, showing various components made by extrusion, sheet forming, and casting processes. Source: Courtesy of ALCOA, Inc.


Properties and Typical Forms of Selected Wrought Magnesium Alloys

TABLE 3.10

Composition (%) Ultimate tensile Yield Elongation

Alloy Al

Zn

Mn

Zr Condition

strength (MPa)

strength (MPa)

in 50 mm (%) Typical forms

AZ31 B 3.0 1.0 0.2 F 260 200 15 Extrusions H24 290 220 15 Sheet and plates AZ80A 8.5 0.5 0.2 T5 380 275 7 Extrusions and

forgings HK31A 3Th 0.7 H24 255 200 8 Sheet and plates ZK60A 5.7 0.55 T5 365 300 11 Extrusions and

forgings


Properties and Typical Applications of Selected Wrought Copper and Brasses

TABLE 3.11 Type and UNS number

Nominal composition (%)

Ultimate tensile

strength (MPa)

Yield

strength (MPa)

Elongation in 50 mm

(%)

Typical applications Electrolytic 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, fire extinguishers, condenser and heat exchanger tubing

Cartridge brass, 70% (C26000)

70.0 Cu, 30.0 Zn 300–900 75–450 66–3 Radiator cores and tanks, flashlight shells, lamp fixtures, fasteners, locks, hinges, ammunition components, 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, propeller shafts, rivets, valve stems, condenser plates


Properties and Typical Applications of Selected Wrought Bronzes

TABLE 3.12

Type and UNS number

Nominal composition (%)

Ultimate tensile

strength (MPa)

Yield

strength (MPa)

Elongation in 50 mm

(%)

Typical applications Architectural bronze (C38500)

57.0 Cu, 3.0 Pb, 40.0 Zn

415 (As extruded)

140 30 Architectural extrusions, store fronts, 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, wire brushes, chemical hardware, textile machinery

Free-cutting phosphor bronze (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, electrical conduits, 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 Selected Nickel Alloys

TABLE 3.13 Properties and Typical Applications of Selected Nickel Alloys (All are Trade Names)

Type and UNS number

Nominal

composition (%)

Ultimate tensile

strength (MPa)

Yield

strength (MPa)

Elongation in 50 mm

(%)

Typical applications Nickel 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 (hot rolled)

30 Cu 525 230 35 Screw-machine products, water meter parts

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

Inconel 600 (annealed) 15 Cr, 8 Fe 640 210 48 Gas turbine parts, heat-treating equipment, electronic parts, nuclear reactors

Hastelloy C-4 (solution-treated and quenched)

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


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

TABLE 3.14 Properties and Typical Applications of Selected Nickel-Base Superalloys at 870 °C (1600 °F) (All are Trade Names)

Alloy

Condition

Ultimate tensile

strength (MPa)

Yield

strength (MPa)

Elongation in 50 mm

(%)

Typical applications Astroloy Wrought 770 690 25 Forgings for high temperature Hastelloy X Wrought 255 180 50 Jet engine sheet parts IN-100 Cast 885 695 6 Jet engine blades and wheels IN-102 Wrought 215 200 110 Superheater and jet engine parts Inconel 625 Wrought 285 275 125 Aircraft engines and structures,

chemical processing equipment lnconel 718 Wrought 340 330 88 Jet engine and rocket parts MAR-M 200 Cast 840 760 4 Jet engine blades MAR-M 432 Cast 730 605 8 Integrally cast turbine wheels René 41 Wrought 620 550 19 Jet engine parts Udimet 700 Wrought 690 635 27 Jet engine parts Waspaloy Wrought 525 515 35 Jet engine parts


Properties and Typical Applications of Selected Wrought Titanium Alloys

TABLE 3.15 Properties and Typical Applications of Selected Wrought Titanium Alloys at Various Temperatures Nominal compos-ition (%) UNS Condition

Ultimate tensile

strength (MPa)


Elonga- tion (%)

Reduc- tion of

area (%) Temp. (°C)

Ultimate tensile

strength (MPa)


Elonga-tion in 50 mm

(%)

Reduc- tion of area Typical Applications

99.5 Ti R50250 Annealed 330 240 30 55 300 150 95 32 80 Airframes; chemical, desalination, and marine parts; plate type heat exchangers

5 Al, 2.5 Sn

R54520 Annealed 860 810 16 40 300 565 450 18 45 Aircraft engine compressor blades and ducting; steam turbine blades

6 Al, 4V

R56400 Annealed 1000 925 14 30 300 725 650 14 35 Rocket motor cases; blades and disks for aircraft turbines and compressors; structural forgings and fasteners; orthopedic implants

425 670 570 18 40 550 530 430 35 50 Solution +

age 1175 1100 10 20 300 980 900 10 28

12 35 22 45 13 V, 11 Cr, 3 Al

R58010 Solution + age

1275 1210 8 — 425 1100 830 12 — High strength fasteners; aerospace components; honeycomb panels


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

TABLE 3.16 Approximate Cost per Unit Volume for Wrought Metals and Plastics Relative to Cost of Carbon Steel Gold Silver Molybdenum alloys Nickel Titanium alloys Copper alloys Zinc alloys Stainless steels

60,000 600 200–250 35 20–40 5–6 1.5–3.5 2–9

Magnesium alloys Aluminum alloys High-strength low-alloy steels Gray cast iron Carbon steel Nylons, acetals, and silicon rubber

*

Other plastics and elastomers*

2–4 2–3 1.4 1.2 1 1.1–2 0.2–1

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


Physical Properties of Material

TABLE 3.17 Physical Properties of Materials, in Descending Order Density Melting point Specific heat Thermal

conductivity Thermal expansion

Electrical conductivity

Platinum Gold Tungsten Tantalum Lead Silver Molybdenum Copper Steel Titanium Aluminum Beryllium Glass Magnesium Plastics

Tungsten Tantalum Molybdenum Columbium Titanium Iron Beryllium Copper Gold Silver Aluminum Magnesium Lead Tin Plastics

Wood Beryllium Porcelain Aluminum Graphite Glass Titanium Iron Copper Molybdenum Tungsten Lead

Silver Copper Gold Aluminum Magnesium Graphite Tungsten Beryllium Zinc Steel Tantalum Ceramics Titanium Glass Plastics

Plastics Lead Tin Magnesium Aluminum Copper Steel Gold Ceramics Glass Tungsten

Silver Copper Gold Aluminum Magnesium Tungsten Beryllium Steel Tin Graphite Ceramics Glass Plastics Quartz


Specific Strength and

Specific Stiffness

Figure 2.29 Specific strength (tensile strength/density) and specific stiffness (elastic modulus/density) for various materials at room temperature. (See also Chapter 9.) Source: M.J. Salkind.


Specific Strength versus Temperature

Figure 2.30 Specific strength (tensile strength/density) for a variety of materials as a function of temperature. Note the useful temperature range for these materials and the high values for composite materials.

the structure of metals

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