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Chapter 11-
Gold, Silver, Copper
Earliest known metals, Why?
•They can be found in metallic state in
nature (not necessarily pure)
•They are malleable
Chapter 11-
Copper History
The name originates from the Latin word cyprium, after the island of Cyprus. Copper was associated with the goddess named Aphrodite / Venus in Greek and Roman mythology.http://www.facts-about.org.uk/science-element-copper.htm
There are reports of copper beads dating back to 9000BCfound in Iraq.
Methods for refining copper from its ores were discovered around 5000BC and a 1000 or so years later it was being used in pottery in North Africa.
around 5000 years ago it was discovered that when copper is mixed with other metals the resulting alloys are harder than copper itself (BRONZE IS COPPER AND TIN)http://www.webelements.com/webelements/scholar/elements/copper/history.html
Chapter 11-
Copper Properties
• Malleable + Durable
• High Electrical/Thermal conductivity
• High corrosion resistance
• Non-Magnetic
Chapter 11-
Copper Properties Electrical/Thermal conductivity
• Highest electrical conductivity (after Silver)
• Used in electrical wiring, pipes, roofing,
Culinary.
Chapter 11-
Copper Odd Facts
• Excessive consumption of foods high in copper, such as
organ meats and oysters can cause Wilson's disease .
• The average home today contains about 400 pounds of
copper for electrical wiring, water pipes and appliances.
• Your refrigerator, dishwasher, microwave, washing
machine and clothes dryer are just a few of the
laborsaving devices in your home that contain copper.
Chapter 11-
Copper Odd Facts
• The Statue of Liberty contains 179,000 pounds of
copper.
• One of copper’s major advantages is that it is
recyclable. In North America alone, approximately
one half of the copper consumed annually comes
from recycled material.
• Copper’s recycle value is so great that premium-
grade scrap has at least 95% of the value of primary
copper from newly mined ore.
• http://www.nwma.org/Education/copper_facts.htm
Chapter 11-
GOLD
• Around 6000 BC
• Main usage was for jewelry
• The name originates from the Old English
Anglo-Saxon word 'geolo' meaning yellow.
The Symbol (Au) Origin is from the Latin
word 'aurum' meaning gold.
Chapter 11-
Gold Properties
• It is extremely malleable
Used in electronic for wiring of the circuits
Chapter 11-
Gold Properties
• Corrosion Resistance
- Used in coins and jewelry
- Gold plating to protect against environment
- Dentistry
Chapter 11-
Gold Properties
• Medicine
Medieval times: gold leaf in water
Now: Goldwasser (Goldwater) liquor
rheumatoid arthritis
implantable insulin pump
Chapter 11-
FAKE GOLD
HOW?
Alloying: All started with Archimedes!
Plating: Thick plating on heavy metal
Mineral:
Fool’s Gold, Pyrite (Iron Sulfide)
Chapter 11-
Gold supply
• Gold is so dense in volume that the total
amount ever mined could be contained in a
cube measuring 62 feet on each side. The
total amount of gold ever mined is 4.2
billion ounces (since 1996).
• Source:http://www.nwma.org/Education/Gold_Facts.htm
Chapter 11-
Silver History
• 4000 BC The area of Anatolia (modern Turkey) is considered the first major source of mined silver.
Names:English: SilverFrench: ArgentGerman: SilberItalian: ArgentoLatin: ArgentumSpanish: Plata
Argentina is named after Silver
Source:http://www.silverinstitute.org
Chapter 11-
Silver Properties Reflectivity
The most reflective metal (specially UV)
– Used in manufacturing of mirrors
– Used for coating telescope mirrors
– Do you remember “silver screen”?
Chapter 11-
Silver Properties Electrical/Thermal
conductivity
• Highest electrical conductivity
• 2nd highest thermal conductivity
(can you guess what is the 1st?)
Used in electronic circuits
Chapter 11-
Silver PropertiesAntibacterial properties
The ancient Phoenicians carried wine in silver containers to keep it fresh.
Colloidal soap bar is being sold .
Silver based water filter is used to remove water born disease agents.
Silver based cleaner are used in swimming pools.
A number of food and beverage makers use silver in food preparation to keep equipment free from bacteria
Commercial air conditioners utilize silver to prevent the buildup of bacteria that cause legionnaires' disease and other airborne illnesses.
Source: http://www.mincosilver.ca/s/Home.asp
Chapter 11-
Silver Applications
• Electronics
• Medicine
• Jewelry
• Currency
• Explosive materials
• Photography
• Sterling silver:92.5% silver and rest other metals (usually copper).
Chapter 11-
Silver Odd Facts
• In India, food can be found decorated with a thin layer of silver, known as Varak.
• Silver is the whitest color of any metal.
• 1/3 of silver goes to photographic film.
• More than 2/3 of the silver produced worldwide is a by product of lead, copper and zinc mining.
• Silver iodide is often used in cloud seeding. A pound of silver iodide is enough to seed many cubic miles of clouds.
Chapter 11-
Silver Odd Facts
• When miners struck gold in Nevada (The Comstock Lode),
the were really slowed down by the huge amounts of gray
clay. It wasn't until later they found out it was silver in the
mud!
• There are no words in the dictionary that rhyme with orange,
purple and SILVER.
• The Olympic gold medal is mostly made of Silver
Chapter 11-
IRON
Timeline• Source of Iron in pre-historical time was
meteorite.
• Earliest production around 2000BC in Anatolia or the Caucasus using bloomeries.
• Cast iron was first produced in China about 550 BC using blast furnace.
Chapter 11-
Time line
• late 1850s, Henry Bessemer invented a new steelmaking process.
• In the 1860s, a rival appeared on the scene: the open-hearth process,developed primarily by the German engineer Karl Wilhelm Siemens. Use of these furnaces ended in US around 1992.
• basic oxygen steelmaking, developed in the 1950s and being used today.
Chapter 11-
Some definitions
• Iron Ore: Raw material containing Iron
• Pig Iron: Immediate product of smelting containing very
high C (3 to 5%)
• Cast Iron: by product of re-melting Pig Iron with scrap iron
(2 to 4% C)
• Steel: Low C Iron (up to 1.7%C)
• Wrought Iron: Commercially pure iron (up to 0.15%C)
• Stainless Steel: Contains at least 10.5 Chromium.
Chapter 11-
Practical
thermomete
r
•White heat •Light Yellow heat•Yellow heat.•Bright red or Light red (Orange) heat.•Full Red heat.•Dark Red or Dull Red heat.•Black heat or Dark Blood Red heat.
Chapter 11-
The Iron Pillar from Delhi7.3 m tall, with one meter below the ground; the diameter is 48 centimeters at the foot, tapering to 29 cm at the top, just below the base of the wonderfully crafted capital; it weighs approximately 6.5 tones, and was manufactured by forged welding.
http://www.world-mysteries.com/sar_ironpillar.htm
Chapter 11-
Steel making
Video Link:
http://www.youtube.com/watch?v=9l7Jqonyo
KA
Chapter 11-
Iron Alloys
Steel (carbon) (category:steels)
Stainless steel (chromium, nickel) AL-6XN
Alloy 20
Celestrium
Marine grade stainless
Martensitic stainless steel
Surgical stainless steel (chromium, molybdenum, nickel)
Silicon steel (silicon)
Tool steel (tungsten or manganese)
Bulat steel
Chromoly (chromium, molybdenum)
Crucible steel
Damascus steel
HSLA steel
High speed steel
Maraging steel
Reynolds 531
Wootz steel
Iron Anthracite iron (carbon) Cast iron (carbon) Pig iron (carbon) Wrought iron (carbon) Fernico (nickel, cobalt) Elinvar (nickel, chromium) Invar (nickel) Kovar (cobalt) Spiegeleisen (manganese, carbon, silicon) Ferroalloys (category:Ferroalloys) FerroboronFerrochromeFerromagnesiumFerromanganeseFerromolybdenumFerronickelFerrophosphorusFerrotitaniumFerrovanadiumFerrosilicon
Chapter 11-
Aluminum (or Aluminum!)
•Aluminum is the most abundant metal in the Earth's crust
(8%), although it is not found free in nature.
•Ancient Greeks and Romans used aluminum salts as dyeing
mordants and as astringents for dressing wounds .
•Hans Christian Ørsted created impure metal in 1825 and in
1827 Friedrich Wöhler isolating aluminum by mixing
anhydrous aluminum chloride with potassium.
Chapter 11-
Aluminum pyramid in Washington memorial
•When Frishmuth submitted his bill for the aluminum pyramid it
was for $256.10
•His original quote was $75 for the aluminum pyramid
•The final price of $225 was agreed upon and was paid.
•Millions of people who had never before even heard about
aluminum now knew what it was.
Chapter 11-
Why Aluminum does not
corrode?• Forms a strong, thin protective oxide layer.
Some other metals (for
example Ti, Cr) have the
same protective layer.
Chapter 11-
Electrical/Thermal conductivity
• has 63% of the electrical conductance of
Copper, but less than half the weight.
• It Is used for electrical wires.
• Aluminum wires are not recommended (and
banned in some places) for house wiring.
WHY?
Chapter 11-
Aluminum Applications
• Aluminum is now the
most used metal (2nd is
steel) in cars today.
Chapter 11-
Aluminum Applications
• 15% of global consumption of Aluminum is beverage cans.
• Used extensively in aircrafts (Up to 80%, 777 has 50% Aluminum and 80 percent of the airframe structure of the F-16 is made from Aluminum).
Chapter 11-
Aluminum Applications
• The Space Shuttle itself burns twice as much aluminum (in the solid rocket booster SRBs) as it does hydrogen (total of the elemental hydrogen in the external tank and the chemically combined hydrogen in the SRB fuel).
• Once the solid fuel has been ignited, there is no stopping the reaction until the fuel is spent; solid booster rockets can't be stopped and restarted like liquid fueled ones.
Chapter 11-
Aluminum recycling facts
•Recycling aluminum saves about 95% of the energy it
would take to produce aluminum from its original source,
bauxite.
•Recycling one aluminum can saves enough electricity
to run a TV for three hours.
•Recycling 40 cans conserves the same energy as one
gallon of gasoline.
•Aluminum recycling is so efficient that it can take as few
as 60 days for a can to be collected, melted down and
made into a new can sitting on a grocery store shelf.
•Can be recycled over and over and over again.
Chapter 11-
106,000 aluminum cans, the
number used in the US every
thirty seconds.
From:http://www.chrisjordan.com/current_set2.php?id=7
Chapter 11-
Tin• Tin was known to the ancients and is
mentioned in the Old Testament.
• Early metal workers found it too soft for
most purposes.
• When mixed with copper becomes Bronze.
• Symbol is Sn (Latin: stannum )
Chapter 11-
Tin usage• Bronze• Bronze is the most popular metal for top-quality bells
and cymbals, and more recently, saxophones.
• It is also widely used for cast metal sculpture. Common bronze alloys often have the unusual and very desirable property of expanding slightly just before they set, thus filling in the finest details of a mold. Bronze parts are tough and typically used for bearings, clips, electrical connectors and springs.
• Bronze also has very little metal-on-metal friction, which made it invaluable for the building of cannons where iron cannonballs would otherwise stick in the barrel.
Chapter 11-
Tin usage• Bronze• It is still widely used today for springs, bearings, bushings,
automobile transmission pilot bearings, and similar fittings, and is particularly common in the bearings of small electric motors.
• Phosphor bronze is particularly suited to precision-grade bearings and springs.
• Bronze is typically 88% copper and 12%. Alpha bronze consists of the alpha solid solution of tin in copper. Alpha bronze alloys of 4–5% tin are used to make coins, springs, turbines and blades.
• Another useful property of bronze is that it is non-sparking. That is, when struck against a hard surface, unlike steel, it will not generate sparks. This is used to advantage to make hammers, mallets, wrenches and other durable tools to be used in explosive atmospheres or in the presence of flammable vapors.
Chapter 11-
Tin usage• Bell metal: hard alloy used for making bells (78%
copper, 22% tin).
• Babbitt metal:
Also called white metal, is an alloy used to provide
the bearing surface in a plain bearing. It was invented
in 1839 by Isaac Babbitt .
Common compositions for Babbitt alloys:
90% tin 10% copper
89% tin 7% antimony 4% copper
80% lead 15% antimony 5% tin
Chapter 11-
Tin usage• Die casting (because of low melting temp.)
• pewter1. between 85 and 99 percent tin, with the remainder consisting of 1-15
percent copper. Some other alloys may contain Lead.
2. Physically, pewter is a bright, shiny metal that is very similar--if not
identical--in appearance to silver.
3. Pewter is a very malleable alloy, being soft enough to carve with hand
tools, and it also takes good impressions from punches or presses.
4. Lead poisoning death could result, leading many to believe tomatoes
(high in acid content) were poisonous for several centuries.
Chapter 11-
Tin usage• Solder: (with a melting point or melting range of
180-190°C )
• Tin plate: sheet steel covered with a thin layer
of tin. Before the advent of cheap mild steel
the backing metal was iron. While once more
widely used, the primary use of tinplate now is
the manufacture of tin cans.
Chapter 11-
Tin usage• Battery grids: Lead-calcium-tin alloys have
been developed for storage-battery grids
largely as replacements for antimonies lead
alloys.
• Dental alloys: or making amalgams contain
silver, tin, mercury, and some copper and zinc.
Chapter 11-
Tin facts• Tin Cry: breaking of the crystals
https://www.youtube.com/watch?v=kzIsvbKHgfU
At temperatures below 13.2oC (55.8oF) the gray powder allotrope begins to show more stability than the white metal allotrope. As temperatures decrease below 13.2oC, the shift from the metallic allotrope to the non-metallic allotrope progresses, reaching a maximum at about -30oC (-22oF).
The gradual disintegration of shiny tin metal into a crumbly, gray powder was observed hundreds of years ago on tin organ pipes housed in unheated northern European cathedrals. With allotropy unknown, the phenomenon was attributed to the work of the Devil
Chapter 11-
Tin facts
The story is often told of Napoleon's men freezing in the bitter Russian winter, their clothes falling apart as tin pest ate the buttons. Most think this is just a story!
Tin ingots stored in St. Petersburg became worthless gray powder following a Russian winter. (Chemists restored the valuable white tin metal by melting the gray allotrope.)
Chapter 11-
Tin facts• Tin foil was once a common wrapping
material for foods and drugs; replaced in the early 20th century by the use of aluminum foil.
• Tin becomes a superconductor below 3.72 K Tin becomes a superconductor below 3.72 K. the Meissner effect was first discovered in superconducting tin crystals.
Chapter 11-
Tin pest https://www.youtube.com/watch?v=FUoVEmHuykM
Tin whisker 1: https://www.youtube.com/watch?v=pGZUdnPoU_I
Tin Whisker 2: ttps://www.youtube.com/watch?v=o758FoVY_8w
Tin whisker 3: https://www.youtube.com/watch?v=goyWEYGKPrQ
Tin whisker 4:
https://www.youtube.com/watch?v=nO-7aFZ8c3E
Chapter 11-
Mercury•Named after the Roman god Mercury, known for speed and mobility
•Also called quicksilver
•Chemical symbol : Hg (Latinized Greek: hydrargyrum, meaning watery or liquid silver .
•Mercury was known to the ancient Chinese and Hindus, and was found in Egyptian tombs that date from 1500 BC.
•China's first emperor, Qin Shi Huang Di —said to have been buried in a tomb that contained rivers of flowing mercury, representative of the rivers of China — was driven insane and killed by mercury pills intended to give him eternal life.
Chapter 11-
Mercury
•The ancient Greeks used mercury in ointments
•Romans used it in cosmetics
•By 500 BC mercury was used to make amalgams with other metals.
•Alchemists often thought of mercury as the First Matter from which all metals were formed
Chapter 11-
Mercury facts• The triple point of mercury, -38.8344 °C, is a
fixed point used as a temperature standard for the International Temperature Scale (ITS-90).
Alexander Calder built a mercury fountain for the Spanish Pavilion at the 1937 World's Fair in Paris.
https://www.youtube.com/watch?v=3OIeEU29kEk
Chapter 11-
Mercury Facts• Mercury was once used as a gun barrel bore
cleaner.
• Mercury was used inside wobbler fishing lures.
• Mercury was used for gold and silver mining.
• Liquid mercury was sometimes used as a coolant
for nuclear reactors.
• Mercury was a propellant for early ion engines in
electric propulsion systems
Chapter 11-
Mercury Facts
• Mercury compounds are found in some over-
the-counter drugs, including topical
antiseptics, stimulant laxatives, diaper-rash
ointment, eye drops, and nasal sprays.
Chapter 11-
Applications
Hat making
• From the mid-18th to the mid-19th centuries, a
process called "carroting" was used in the making of
felt hats. Animal skins were rinsed in an orange
solution of the mercury compound mercuric nitrate,
Hg(NO3)2·2H2O. This process separated the fur
from the pelt and matted it together.
Chapter 11-
ApplicationsMedicine
• Mercury (I) chloride (Hg2Cl2 has traditionally been used as a diuretic, topical disinfectant, and laxative. •Mercury (II) chloride (HgCl2) was once used to treat syphilis (along with other mercury compounds), although it is so toxic that sometimes the symptoms of its toxicity were confused with those of the syphilis it was believed to treat. It was also used as a disinfectant. •Blue mass, a pill or syrup in which mercury is the main ingredient, was prescribed throughout the 1800s for numerous conditions including constipation, depression, child-bearing and toothaches. •In the early 20th century, mercury was administered to children yearly as a laxative and de-wormer, and it was used in teething powders for infants. Since the 1930s some vaccines have contained the preservative thiomersal, which is metabolized or degraded to ethyl mercury. Although it was widely speculated that
Chapter 11-
Applications
Dentistry•Elemental mercury is the main ingredient in dental amalgams. •Controversy over the health effects from the use of mercury amalgams began shortly after its introduction into the western world, nearly 200 years ago. •In 1845, The American Society of Dental Surgeons, concerned about mercury poisoning, asked its members to sign a pledge that they would not use amalgam. The ASDS disbanded in 1865. •The American Dental Association formed three years after and currently takes the position that "amalgam is a valuable, viable and safe choice for dental patients,“. •In 1993, the United States Public Health Service reported that "amalgam fillings release small amounts of mercury vapor," but in such a small amount that it
Chapter 11-
Applications
INDUSTRIAL:
•The red mercury oxide is used in mercury batteries, developed during II World War, which are compact and stable energy sources.
•The major applications of mercury are in electrical equipment and in control devices, where the fluidity stability, high density and electrical conductivity are essential.
Chapter 11-
Applications
Motor
https://www.youtube.com/watch?v=1fRC7V3KMA4
Chapter 11-
Mercury Poisoning
• Symptoms included tremors, emotional
lability, insomnia, dementia and
hallucinations.
Video Link:
http://www.youtube.com/watch?v=JABbof
wD3MI
Chapter 11- 2
Adapted from Fig. 9.21,Callister 6e.
(Fig. 9.21 adapted from Binary Alloy Phase Diagrams, 2nd ed.,
Vol. 1, T.B. Massalski (Ed.-in-Chief),
ASM International, Materials Park,
OH, 1990.)
Adapted from
Fig. 11.1,
Callister 6e.
TAXONOMY OF METALS
Chapter 11- 3Based on data provided in Tables 11.1(b), 11.2(b), 11.3, and 11.4, Callister 6e.
STEELS
Chapter 11-76
Ferrous Alloys
Iron-based alloys
Nomenclature for steels (AISI/SAE)
10xx Plain Carbon Steels
11xx Plain Carbon Steels (resulfurized for machinability)
15xx Mn (1.00 - 1.65%)
40xx Mo (0.20 ~ 0.30%)
43xx Ni (1.65 - 2.00%), Cr (0.40 - 0.90%), Mo (0.20 - 0.30%)
44xx Mo (0.5%)
where xx is wt% C x 100
example: 1060 steel – plain carbon steel with 0.60 wt% C
Stainless Steel >11% Cr
• Steels
• Cast Irons
Chapter 11- 4
NonFerrous Alloys
• Cu AlloysBrass: Zn is subst. impurity (costume jewelry, coins, corrosion resistant)Bronze: Sn, Al, Si, Ni are subst. impurity (bushings, landing gear)Cu-Be: precip. hardened for strength
• Al Alloys-lower : 2.7g/cm3
-Cu, Mg, Si, Mn, Zn additions -solid sol. or precip. strengthened (struct.
aircraft parts & packaging)
• Mg Alloys-very low : 1.7g/cm3
-ignites easily -aircraft, missles
• Refractory metals-high melting T -Nb, Mo, W, Ta• Noble metals
-Ag, Au, Pt -oxid./corr. resistant
• Ti Alloys-lower : 4.5g/cm3
vs 7.9 for steel -reactive at high T -space applic.
Based on discussion and data provided in Section 11.3, Callister 6e.
NONFERROUS ALLOYS
Chapter 11-
Cast Iron:
Past Semester Project
Chapter 11-79
Cast Irons
• Ferrous alloys with > 2.1 wt% C
– more commonly 3 - 4.5 wt% C
• Low melting – relatively easy to cast
• Generally brittle
• Cementite decomposes to ferrite +
graphite
Fe3C 3 Fe (α) + C (graphite)
– generally a slow process
Chapter 11-80
Types of Cast Iron
Gray iron
• graphite flakes
• weak & brittle in tension
• stronger in compression
• excellent vibrational dampening
• wear resistant
Ductile iron
• add Mg and/or Ce
• graphite as nodules not flakes
• matrix often pearlite – stronger
but less ductile
Figs. 11.3(a) & (b),
Callister &
Rethwisch 9e.[Courtesy of C. H.
Brady and L. C. Smith,
National Bureau of
Standards, Washington,
DC (now the National
Institute of Standards
and Technology,
Gaithersburg, MD]
Chapter 11-81
Types of Cast Iron (cont.)
White iron
• < 1 wt% Si
• pearlite + cementite
• very hard and brittle
Malleable iron
• heat treat white iron at 800-900°C
• graphite in rosettes
• reasonably strong and ductile
Figs. 11.3(c) & (d),
Callister &
Rethwisch 9e.
Co
urtesy
of A
mcast In
dustrial C
orp
oratio
n
Rep
rinted
with
perm
ission o
f the
Iron C
astings S
ociety
, Des P
laines, IL
Chapter 11-82
Types of Cast Iron (cont.)
Compacted graphite iron
• relatively high thermal conductivity
• good resistance to thermal shock
• lower oxidation at elevated
temperatures
Fig. 11.3(e), Callister & Rethwisch 9e.
Co
urtesy
of S
inter-C
ast, Ltd
.
Chapter 11-83
Production of Cast Irons
Fig.11.5, Callister & Rethwisch 9e.(Adapted from W. G. Moffatt, G. W.
Pearsall, and J. Wulff, The Structure and
Properties of Materials, Vol. I, Structure, p.
195. Copyright © 1964 by John Wiley &
Sons, New York. Reprinted by permission of
John Wiley & Sons, Inc.)
Chapter 11-84
Limitations of Ferrous Alloys
1) Relatively high densities
2) Relatively low electrical conductivities
3) Generally poor corrosion resistance
Chapter 11-87
Metal Fabrication
• How do we fabricate metals?
– Blacksmith - hammer (forged)
– Cast molten metal into mold
• Forming Operations
– Rough stock formed to final shape
Hot working vs. Cold working• Deformation temperature
high enough for
recrystallization
• Large deformations
• Deformation below
recrystallization
temperature
• Strain hardening occurs
• Small deformations
Chapter 11- 6
Ao Ad
force
die
blank
force
• Forging
(wrenches, crankshafts)
FORMING
• Drawing
(rods, wire, tubing)
often at
elev. T
• Rolling
(I-beams, rails)
• Extrusion
(rods, tubing)
Adapted from
Fig. 11.7,
Callister 6e.
tensile force
Ao
Addie
die
METAL FABRICATION METHODS-I
Chapter 11-
Forging:
http://www.youtube.com/watch?v=mRA6RY2o9Lg
Rolling:
https://www.youtube.com/watch?v=wBXexkRsAJg
Drawing:
https://www.youtube.com/watch?v=2ph3AOxvcR4
Extrusion:
https://www.youtube.com/watch?v=Y75IQksBb0M
Chapter 11-
plaster
die formed
around wax
prototype
8
CASTING
• Sand Casting
(large parts, e.g.,
auto engine blocks)
• Investment Casting
(low volume, complex shapes
e.g., jewelry, turbine blades)
• Die Casting
(high volume, low T alloys)
• Continuous Casting
(simple slab shapes)
METAL FABRICATION METHODS-II
Chapter 11-
Investment Casting
https://www.youtube.com/watch?v=tyrXq_u1OH0
Chapter 11- 9
CASTINGFORMING JOINING
• Powder Processing
(materials w/low ductility)
• Welding
(when one large part is
impractical)
• Heat affected zone:
(region in which the
microstructure has been
changed).
Adapted from Fig.
11.8, Callister 6e.
(Fig. 11.8 from
Iron Castings Handbook, C.F.
Walton and T.J.
Opar (Ed.), 1981.)
piece 1 piece 2
fused base metal
filler metal (melted)base metal (melted)
unaffectedunaffectedheat affected zone
METAL FABRICATION METHODS-III
Chapter 11-
Laser
Video Links:
http://www.youtube.com/watch?v=PlF_oXvbu4s
http://www.youtube.com/watch?v=N7NofmHWWPQ
http://www.youtube.com/watch?v=JKHXxLvsAMA
http://www.youtube.com/watch?v=1IhpaVRbMvA
Chapter 11-
Friction Welding
https://www.youtube.com/watch?v=tyrXq_u1OH0
Chapter 11- 10
Annealing: Heat to Tanneal, then cool slowly.
Based on discussion in Section 11.7, Callister 6e.
THERMAL PROCESSING OF METALS
Chapter 11-107
Hardenability -- Steels• Hardenability – measure of the ability to form martensite
• Jominy end quench test used to measure hardenability.
• Plot hardness versus distance from the quenched end.
Fig. 11.12, Callister &
Rethwisch 9e. (Adapted from A.G. Guy,
Essentials of Materials Science,
McGraw-Hill Book Company,
New York, 1978.)
Fig. 11.13, Callister &
Rethwisch 9e.
24°C water
specimen (heated to γ
phase field)
flat ground
Rockwell C
hardness tests
Hard
ness,
HR
C
Distance from quenched end
Chapter 11-
Video
• https://www.youtube.com/watch?v=qjsZVi
vfzcg
• https://www.youtube.com/watch?v=nEV6R
qDr9CA
Chapter 11-109
Hardenability vs Alloy Composition
• Hardenability curves for
five alloys each with,
C = 0.4 wt% C
• "Alloy Steels"(4140, 4340, 5140, 8640)
-- contain Ni, Cr, Mo
(0.2 to 2 wt%)
-- these elements shift
the "nose" to longer times
(from A to B)
-- martensite is easier
to form
Fig. 11.15, Callister & Rethwisch 9e. (Adapted from figure furnished courtesy
Republic Steel Corporation.)
Cooling rate (°C/s)
Ha
rdn
ess, H
RC
20
40
60
100 20 30 40 50Distance from quenched end (mm)
210100 3
4140
8640
5140
50
80
100
%M4340
T(°C)
10-1
10 103
1050
200
400
600
800
Time (s)
M(start)
M(90%)
BA
TE
Chapter 11-110
• Effect of quenching medium:
Medium
air
oil
water
Severity of Quench
low
moderate
high
Hardness
low
moderate
high
• Effect of specimen geometry:
When surface area-to-volume ratio increases:
-- cooling rate throughout interior increases
-- hardness throughout interior increases
Position
center
surface
Cooling rate
low
high
Hardness
low
high
Influences of Quenching Medium & Specimen
Geometry
Chapter 11-
• Particles impede dislocation motion.
• Ex: Al-Cu system
• Procedure:
111
0 10 20 30 40 50wt% Cu
L+Lα
α+θθ
θ+L
300
400
500
600
700
(Al)
T(ºC)
composition range available for precipitation hardening
CuAl2
A
Fig. 11.25, Callister & Rethwisch 9e. (Adapted from J.L. Murray, International
Metals Review 30, p.5, 1985. Reprinted by
permission of ASM International.)
Precipitation Hardening
Adapted from Fig.
11.23, Callister &
Rethwisch 9e.
-- Pt B: quench to room temp.
(retain α solid solution)
-- Pt C: reheat to nucleate
small θ particles within
α phase.• Other alloys that precipitation
harden:• Cu-Be
• Cu-Sn
• Mg-Al
Temp.
Time
-- Pt A: solution heat treat
(get α solid solution)
Pt A (sol’n heat treat)
B
Pt B
C
Pt C (precipitate )
Chapter 11-112
• 2014 Al Alloy:
• Maxima on TS curves.
• Increasing T accelerates
process.
Fig. 11.28, Callister & Rethwisch 9e. [Adapted from Metals Handbook: Properties and Selection: Nonferrous Alloys
and Pure Metals, Vol. 2, 9th ed., H. Baker (Managing Ed.), 1979. Reproduced by permission of ASM International,
Materials Park, OH.]
Influence of Precipitation Heat Treatment on
TS, %EL
precipitation heat treat time
tensile
str
ength
(M
Pa
)
200
300
400
1001min 1h 1day 1mo 1yr
204ºC149ºC
• Minima on %EL curves.
%E
L(2
in s
am
ple
)10
20
30
01min 1h 1day 1mo 1yr
204ºC 149ºC
precipitation heat treat time
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