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									Assignment:          Homework 5
Name:                Bayan Salone
Course:              IEGR 309 Materials Engineering
Semester:            Spring 2001
Professor:           M. Salimian




Department:   Industrial Engineering, Manufacturing and Information Engineering
Date:         February 25, 2001
          Titanium is one of the earth’s precious metals. Titanium is a transition metal that
is mainly used to make alloys. In this installment of the element series,
Titanium’s physical and mechanical properties, manufacturing, processing, and economic
worth will be discussed in detail. Titanium, symbol Ti, silver-white metallic element used
principally to make light, strong alloys. Titanium is one of the transition elements of the
periodic table (see Periodic Law). The atomic number of titanium is 22.
Titanium was discovered in 1791 in the mineral menachanite by the British clergyman
William Gregor, who named the new element menachite. Four years later, the German
chemist Martin Heinrich Klaproth rediscovered the element in the mineral rutile and
named it titanium in allusion to the strength of the mythological Greek Titans. The metal
was isolated in 1910.
Pure titanium is soluble in concentrated acids, such as sulfuric and hydrofluoric acids,
and insoluble in water. The metal is extremely brittle when cold, but is readily malleable
and ductile at a low red heat. Titanium melts at about 1660° C (about 3020° F), boils at
about 3287° C (about 5949° F), and has a specific gravity of 4.5. The atomic weight of
titanium is 47.88.
Titanium burns in oxygen at 610° C (1130° F) to form titanium dioxide, and it burns in
nitrogen at 800° C (1472° F) to form titanium nitride, TiN. Titanium exhibits valences of
4, 3, and 2, and forms the salts titanium tetrachloride, TiCl4; titanium trichloride, TiCl3;
and titanium dichloride, TiCl2. It ranks ninth in abundance among the elements in the
crust of the earth but is never found in the pure state. It occurs as an oxide in the minerals
ilmenite, FeTiO3; rutile, TiO2; and sphene, CaO · TiO2· SiO2.
To obtain titanium oxide, the mineral is ground and mixed with potassium carbonate and
aqueous hydrofluoric acid to yield potassium fluorotitanate, K2TiF6. The fluorotitanate is
extracted with hot water and decomposed with ammonia. The resulting ammoniacal
hydrated oxide, when ignited in a platinum vessel, yields titanium dioxide, TiO2.
Titanium is obtained in the pure form by first treating the oxide with chlorine to form
titanium tetrachloride, a volatile liquid, and then reducing the liquid with magnesium in a
closed iron chamber to yield metallic titanium. The metal is then melted and cast into
ingots.
       Because of its strength and lightweight, titanium is used in metallic alloys and as
a substitute for aluminum. Alloyed with aluminum and vanadium, titanium is used in
aircraft for firewalls, outer skin, landing-gear components, hydraulic tubing, and engine
supports. The compressor blades, disks, and housings of jet engines are also made of
titanium. A commercial jet transport uses between 318 and 1134 kg (700 and 2500 lb) of
the metal. A supersonic transport, flying at speeds between 2410 and 3220 km/h (about
1500 and 2000 mph), uses from 14 to 45 metric tons of titanium. Titanium is also widely
used in missiles and space capsules. The Mercury, Gemini, and Apollo capsules were
made largely of titanium. Other common titanium alloys include ferrocarbon titanium,
made by reduction of ilmenite with coke in an electric furnace; cuprotitanium, formed by
reduction of rutile to which copper has been added; and manganotitanium, produced by
reduction of rutile to which manganese or oxides of manganese have been added.
The relative inertness of titanium makes it available as a replacement for bone and
cartilage in surgery and as a pipe and tank lining in the processing of foods. It is used in
heat exchangers in desalinization plants because of its ability to withstand saltwater
corrosion. In metallurgy, titanium alloys are employed as deoxidizers and denitrogenizers
to remove oxygen and nitrogen from molten metals. Titanium dioxide, known as titanium
white, is a brilliant white pigment used in paints, lacquers, plastics, paper, textiles, and
rubber (1). Below is a chart that features the general characteristics of titanium.




General
     Name               Titanium                        Symbol          Ti
 atomic number          22                          Atomic weight       47.90
 Density @ 293 K        4.50 g/cm3                  Atomic volume       10.64 cm3/mol
     Group              Trans. Met.                   discovered        1791


States
                        state (s, l,
                                     s
                            g)
                         melting
                                     1933.2 K boiling point 3558 K
                           point
                         Heat of 15.450              Heat of  421.00
                          fusion kJ/mol          vaporization kJ/mol
                                           Back to the top
  Energies
   1st ionization energy       658 kJ/mole                      electronegativity      1.54
   2nd ionization energy       1310.3 kJ/mole                   electron affinity      7.6 kJ/mole
   3rd ionization energy       2652.5 kJ/mole                     Specific heat        0.52 J/gK
     heat atomization          470 kJ/mole atoms


  Oxidation & Electrons
           Shells                  2,8,10,2              electron configuration        [Ar] 3d2 4s2
  minimum oxidation number         -1                maximum oxidation number          4
  min. common oxidation no.        0                  max. common oxidation no.        4
                                              Back to the top

  Appearance & Characteristics
structure hcp: hexagonal close pkd                     color         gray
  uses    steel,white pigment(TiO2)                   toxicity
hardness mohs                                      characteristics   max strength/weight ratio


  Reactions
   reaction with air  mild, w/ht =>TiO2, TiN                    reaction with 6M HCl none
 reaction with 6M HCl none                                    reaction with 15M HNO3 passivated
reaction with 6M NaOH none
                                       Back to the top

  Other Forms
 number of isotopes      5                                     hydride(s)     TiH2
     oxide(s)            TiO Ti2O3 TiO2 + more                 chloride(s)    TiCl2 TiCl3 TiCl4


  Radius
       ionic radius (2- ion)           pm                     ionic radius (1- ion)              pm
          atomic radius                147 pm                 ionic radius (1+ ion)              pm
       ionic radius (2+ ion)           100 pm                 ionic radius (3+ ion)              81 pm
                                            Back to the top

  Conductivity
 thermal conductivity     21.9 J/m-sec-deg             electrical conductivity      23.81 1/mohm-cm
     polarizability       14.6 A^3


  Abundance
       source           Ilmenite, rutile(oxide)               rel. abund. solar system      3.380 log
abundance earth's crust 3.8 log                                       cost, pure            6.1 $/100g
      cost, bulk        $/100g
The image below is a schematic representation of the shell structure of titanium - not
what the atom of titanium "looks like".
The following represents the electronic configuration and its associated term symbol for
the ground state neutral gaseous atom. The configuration associated with titanium in
its compounds is not necessarily the same.
      Ground state electron configuration: [Ar].3d2.4s2
      Shell structure: 2.8.10.2
      Term symbol: 3F2




1. The images on the following pages are pictures of titanium’s crystal structure.
Here is some information about the crystal structure of titanium.
       Space group:          P63/mmc (Space group number: 194)
         Structure:          hcp (hexagonal close-packed)
Cell parameters:     a /pm     b /pm     c /pm      a/°     b/°       g/°
                   295.08    295.08    468.55    90.000   90.000   120.000
       Next we will take a look at some of the products that titanium is used in. Titanium
is used in a variety of products ranging from airplanes to golf clubs. What do the Boeing
777, Spain's Guggenheim museum and the 2001 Corvette Z06 have in common? In a
word, titanium -- and plenty of it. The latest Boeing airliner uses more of it than any other
aircraft, the now-famous museum is clad in the metal, and the Z06 -- a lightweight, high-
performance option package for Chevrolet's sports car -- boasts the first mass-produced
exhaust made of titanium.
Widely utilized in the aerospace industry for its high tensile strength, high strength-to-
weight ratio, long fatigue life and corrosion resistance, titanium (Ti) has made little
headway in the automotive industry, due mainly to high cost. The Corvette Z06
introduction may change that.
The few production Ti applications thus far are all in the powertrain arena, and all are
from Japanese OEMs: connecting rods in the Acura NSX V-6 engine and valves in
Infiniti's 2002 V-8. A new Yamaha 250cc motocross engine also sports Ti valves. Now,
exhaust system supplier ArvinMeritor, and Titanium Metals Corporation (TIMET), the
world's largest Ti manufacturer; believe the time is right for a significant push into the
auto industry. The two companies co-developed the 26-pound Z06 exhaust system, which
is 44 percent lighter than the Corvette's standard 46-pound stainless steel system.
"This is the single greatest bolt-on weight reduction available today," claims Kurt Faller,
of Denver-based TIMET. Ti is two-fifths lighter than steel, with equal strength. It has
natural corrosion immunity to road salts and sulfur-rich engine exhaust that prevents the
system from pitting or rusting.
Besides exhaust systems, Faller sees other potential applications for Ti on vehicles --
including coil springs, driveshafts, brake caliper pistons and door intrusion beams.
Switching to Ti con rods in higher rewing engines can help eliminate balance shafts, he
says.
Faller acknowledges that cost is an issue, and would likely preclude near-term Ti use in
small or mid-range cars. Yet he sees big potential for the metal in the luxury car sector,
where a Ti exhaust could bring a car back into a lower weight class.
TI's cost premium is not in the raw material -- it is the fourth-most abundant structural
element, occurring in common black beach sand. The cost is inherent in the refining
process, and in parts manufacturing. Because it absorbs oxygen which embrittles it during
the melting process, any hot processing of Ti (including welding) is done under vacuum
or with inert gas. Then it must be surface etched or ground. Machining it requires special
tools, techniques and expertise.
Welding Ti is an extremely delicate process, ads Graham Thieman, ArvinMeritor director
of engineering. He claims that Arvin's unique weld shielding process results in welds that
are "totally immune to any form of corrosion for the life of the vehicle."
For its part, Indiana-based Arvin has been investigating the use of Ti for exhaust systems
since 1993. Although the exotic, McLaren F1 supercar of the mid-1990s featured a
titanium exhaust, the Z06 Corvette is the first major automotive application. (The
material is gaining popularity in aftermarket exhausts, notably superbike systems.)
Highly efficient gas turbine engines are possible only through the use of titanium-based
alloys in components like fan blades, compressor blades, discs, hubs and numerous non-
rotor parts. The key advantages of titanium-based alloys in this application include high
strength/weight ratio, strength at moderate temperatures and good resistance to creep and
fatigue. The development of titanium aluminides will allow the use of titanium in hotter
sections of a new generation of engines.
A major industrial application for titanium remains in heat transfer applications in which
the cooling medium is seawater, brackish water or polluted water. Titanium condensers,
shell and tube heat exchangers, and plate and frame heat exchangers are used extensively
in power plants, refineries, air conditioning systems, chemical plants, offshore platforms,
surface ships and submarines.
    The life span and dependability of titanium are demonstrated by the fact that of the millions
    of feet of welded titanium tubing in power plant condenser service, there have been no
    reported failures due to corrosion on the cooling water side.
    The unique electrochemical properties of the titanium DSA make it the most energy
    efficient unit for the production of chlorine, chlorate and hypochlorite.


 In desalination, excellent resistance to corrosion, erosion, and high condensation efficiency
 make titanium the most cost-effective and dependable material for critical segments of
 desalination plants. Increased usage of very thin walled welded tubing makes titanium
 competitive with copper-nickel.
 Hydrometallurgical extraction of metals from ores in titanium reactors is an environmentally
 safe alternative to smelting processes. Extended lifespan, increased energy efficiency, and
 greater product purity are factors promoting the usage of titanium electrodes in electro-
 winning and electro-refining of metals like copper, gold, manganese and manganese dioxide.
 Medical titanium is widely used for implants, surgical devices, pacemaker cases and
 centrifuges. Titanium is the most biocompatible of all metals due to its total resistance to
 attack by body fluids, high strength and low modulus.
 In hydrocarbon processing, the need for longer equipment life, coupled with requirements for
 less downtime and maintenance, favor the use of titanium in heat exchangers, vessels,
 columns and piping systems in refineries, LNG plants and offshore platforms. Titanium is
 immune to general attack and stress corrosion cracking by hydrocarbons, H2S, brines and
 CO2.
           Because of high toughness, high strength and exceptional erosion/corrosion
   resistance, titanium is currently being used for submarine ball valves, fire pumps, heat
   exchangers, castings, hull material for deep-sea submersibles, water jet propulsion
   systems, and shipboard cooling and piping systems. Titanium vessels, heat-exchangers,
   tanks, agitators, coolers, and piping systems are utilized in the processing of aggressive
   compounds, like nitric acid, organic acids, chlorine dioxide, inhibited reducing acids and
   hydrogen sulfide.
Titanium is a standard material for orthopaedic devices such as hip joints, bone screws, knee
joints, bone plates and dental implants due to the outstanding strength to weight ratio of the
material and its immunity to body fluids.




The body readily accepts titanium since it is more biocompatible that stainless steel or cobalt
chrome. Titanium also has a higher fatigue strength than many other metals. The unique qualities
of titanium prove to be MRI (Magnetic Resonance Imaging) and CT (Computed Tomography)
compatible.


The machinability of titanium is comparable to most stainless steels and better than cobalt
chrome. Sharp, clean tools with good chip removal and ample coolant are recommended when
drilling, turning, milling or cold sawing titanium. The work hardening rate for titanium is less
than stainless steel. See our on-line Technical Brochure for additional machining information.


Through our international service center network, Titanium Industries, Inc. maintains an
extensive inventory of orthopaedic bar, billet, plate, sheet and wire products. We provide prompt
shipment for orders of standard mill shapes, and have the capability to cut custom parts to
especially close tolerances. See our products page for our complete list of titanium products.


Titanium Industries, Inc. supplies titanium products, which meet customer specifications.
Chemical and mechanical-property test reports accompany each Titanium Industries, Inc.
shipment. Inventory is 100% traceable from mill processing through melt source to maintain
quality control requirements. Titanium Industries has achieved ISO 9002 certification in our
United States, Canadian and British facilities.


Our Applications and Development Center can assist you in prototype work.


Tests and inspection ensure our titanium products meet destructive and non-destructive tests
according to industry and customer specifications.


Types Of Testing Provided
Chemical                 Final Hydrogen           Tensile/Yield              Beta Transus
Micro Structure          Macro Structure          Eddy Current               Ultrasonic
Dimensional              Straightness             Roundness                  Stress Rupture
Heat Treatments          Annealing                Stress Relieving           Elevated Temp


Orthopaedic Specifications
ASTM F-67-
                     Unalloyed titanium for surgical implant applications.
68(94)E1
ASTM F-136-
                     Wrought titanium 6Al-4V ELI Alloy for surgical implant applications.
92E1
ASTM F 1472-93 Wrought titanium 6Al-4V Alloy for surgical implant applications.


           As one can note from this research paper, titanium is used in a wide variety of
   products. Titanium is applied to numerous industrial machines and medical aids that
   assist human beings every day. Titanium is yet another valuable element with an
   extremely important economic worth. It’s ductility and malleability make titanium one of
   the more resourceful alloys.
                                    References


1. www.msn.com: “http://encarta.msn.com/find/Concise.asp?ti=045A1000” 2-25-01
2. www.chemicool.com: “http://www.chemicool.com/elements/titanium.html” 2-25-01
3. www.webelements.com:
   “http://www.webelements.com/webelements/elements/text/Ti/econ.html” 2-25-01
4. www.titanium.com:
   “http://www.alleghenytechnologies.com/titanium/pages/uses/aerospac.htm” 2-25-01

								
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