TOPIC #Write a report on Aluminum alloys used for

spacecraft shuttle and its properties.

Submitted to: Submitted by:

Mr. Piyush Chandra Verma Shyam Kuvar Yadav

Lecturer, Roll no-B35

Lovely Professional University Sec- B4911

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Index1. Declaration ……………………… 032. Acknowledgment ……………………… 043. Preface ……………………… 054. Introduction ……………………… 06

5. Wrought aluminium ………………………. 066. Cast aluminium ………………………… 07

7. Superplastic aluminium ……………………………... 098. Aluminium alloys used for Spacecraft Shuttle ………... 109. Properties of Aluminium Alloys ……………………….. 12

10. References ……………………... 16

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DECLARATION

I, Shyam Kuvar Yadav student of Lovely Professional University have completed the term paper on:

Write a report on Aluminum alloys used for spacecraft shuttle and its properties.

The information given in this term paper is true to the best of my knowledge.

(SHYAM KUVAR YADAV)

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ACKNOWLEDGEMENT

First of all I would like to thank the Lovely University and take the opportunity to do this project as a part of the B.TECH(ME)

Many people have influenced the shape and content of this term paper, and many supported me through it. I express my sincere gratitude to Mr.Piyush Chandra Verma for assigning me a term paper on Material Science, which is an interesting and exhaustive subject.

He has been an inspiration and role model for this topic. His guidance and active support has made it possible to complete the assignment.

I also would like to thank my Friends who have helped and encouraged me throughout the working of the term paper.

Last but not the least I would like to thank the Almighty for always helping me.

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Introduction:

Though light in weight, commercially pure aluminum has a tensile strength of about 13,000

psi. Cold working the metal approximately doubles its strength. In other attempts to increase

strength, aluminum is alloyed with elements such as manganese, silicon, copper, magnesium,

or zinc. The alloys can also be strengthened by cold working. Some alloys are further

strengthened and hardened by heat treatments. At subzero temperatures, aluminum is stronger

than at room temperature and is no less ductile. Most aluminum alloys lose strength at

elevated temperatures, although some retain significant strength to 500°F. Besides a high

strength-to-weight ratio and good formability, aluminum also possesses its own anticorrosion

mechanism. When exposed to air, aluminum does not oxidize progressively because a hard,

microscopic oxide coating forms on the surface and seals the metal from the environment.

The tight chemical oxide bond is the reason that aluminum is not found in nature; it exists

only as a compound.

Aluminum and its alloys, numbering in the hundreds, are available in all common

commercial forms. Aluminum-alloy sheet can be formed, drawn, stamped, or spun. Many

wrought or cast aluminum alloys can be welded, brazed, or soldered, and aluminum surfaces

readily accept a wide variety of finishes, both mechanical and chemical. Because of their high

electrical conductivity, aluminum alloys are used as electrical conductors. Aluminum reflects

radiant energy throughout the entire spectrum, is nonsparking, and nonmagnetic.

Wrought aluminum:

A four-digit number that corresponds to a specific alloying element combination usually

designates wrought aluminum alloys. This number is followed by a temper designation that

identifies thermal and mechanical treatments.

To develop strength, heat-treatable wrought alloys are solution heat treated, then quenched

and precipitation hardened. Solution heat treatment consists of heating the metal, holding at

temperature to bring the hardening constituents into solution, then cooling to retain those

constituents in solution. Precipitation hardening after solution heat treatment increases

strength and hardness of these alloys.

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While some alloys age at room temperature, others require precipitation heat treatment at an

elevated temperature (artificial aging) for optimum properties. However, distortion and

dimensional changes during natural or artificial aging can be significant. In addition,

distortion and residual stresses can be introduced during quenching from the solution heat-

treatment cycle. These induced changes can be removed by deforming the metal (for

example, stretching).

Wrought aluminum alloys are also strengthened by cold working. The high-strength alloys --

either heat treatable or not -- work harden more rapidly than the lower-strength, softer alloys

and so may require annealing after cold working. Because hot forming does not always work

harden aluminum alloys, this method is used to avoid annealing and straightening operations;

however, hot forming fully heat-treated materials is difficult. Generally, aluminum

formability increases with temperature.

Recently developed aluminum alloys can provide nearly custom-engineered strength, fracture

toughness, fatigue resistance, and corrosion resistance for aircraft forgings and other critical

components. The rapid-solidification process is the basis for these new alloy systems, called

wrought P/M alloys. The term wrought P/M is used to distinguish this technology from

conventional press-and-sinter P/M technology. Grades 7090 and 7091 are the first

commercially available wrought P/M aluminum alloys. These alloys can be handled like

conventional aluminum alloys on existing aluminum-fabrication facilities.

Other significant new materials are the aluminum-lithium alloys. These lightweight metals

are as strong as alloys now in use and can be fabricated on existing metalworking equipment.

Although impressive structural weight reductions (from 7 to 10%) are possible through direct

substitution, even greater reduction (up to 15%) can be realized by developing fully

optimized alloys for new designs. Such alloys would be specifically tailored to provide

property combinations not presently available. Producing an alloy that will provide these

combinations is the object of second and third-generation low-density alloy development

efforts.

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Cast aluminum:

Aluminum can be cast by all common casting processes. Aluminum casting alloys are

identified with a unified, four-digit (xxx.x) system. The first digit indicates the major alloying

element. For instance, 100 series is reserved for 99% pure aluminum with no major alloying

element used. The second and third digits in the 100 series indicate the precise minimum

aluminum content. For example, 165.0 has a 99.65% minimum aluminum content. The 200-

900 series designate various aluminum alloys, with the second two digits assigned to new

alloys as they are registered. The fourth digit indicates the product form. Castings are

designated 0; ingots are designed 1 or 2.

Letter prefixes before the numerical designation indicate special control of one or more

elements or a modification of the original alloy. Prefix X designates an experimental

composition. The material may retain the experimental designation up to five years. Limits

for the experimental alloy may be changed by the registrant.

Commercial casting alloys include heat-treatable and nonheat-treatable compositions. Alloys

that are heat treated carry the temper designations 0, T4, T5, T6, and T7. Die castings are not

usually solution heat treated because the temperature can cause blistering.

Permanent-mold casting technology involves several variations having to do with how the

metal gets into the mold cavity. Initially, molds were simply gravity filled from ladles, in the

same manner as sand molds. Subsequently, low pressure on the liquid-metal surface of a

crucible was used to force the metal up, through a vertical tube, into the mold cavity. This

refinement produces castings with higher mechanical properties and is more economical than

gravity filling because extensive gates and risers are unnecessary.

More recently, the process was modified to use a low level of vacuum drawn on the mold

cavity, causing atmospheric pressure to force the molten metal up into the mold. This process

variation, together with controlled and rapid solidification, increases properties further

because it produces castings that are almost entirely free of porosity.

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Although both variations improve properties and speed casting cycles, the added equipment

complexities limit the casting size that can be handled. Consequently, all three permanent-

mold processes are in use today, turning out aluminum castings weighing from less than one

pound to several hundred pounds.

Aluminum matrix composites: Metal matrix composites (MMCs) consist of metal alloys

reinforced with fibers, whiskers, particulates, or wires. Alloys of numerous metals

(aluminum, titanium, magnesium and copper) have been used as matrices to date.

Recent MMC developments, however, seem to thrust aluminum into the spotlight. In the

NASA space shuttle, for example, 240 struts are made from aluminum reinforced with boron

fibers. Also, aluminum diesel-engine pistons that have been locally reinforced with ceramic

fibers are eliminating the need for wear-resistant nickel-cast iron inserts in the automotive

environment.

Fabrication methods differ for both products. Monolayer tapes in the space shuttle struts are

wrapped around a mandrel and hot isostatically pressed to diffusion bond the layers. For the

pistons, a squeeze-casting process infiltrates liquid metal into a fiber preform under pressure.

Other fabrication methods for MMCs include: hot pressing a layer of parallel fibers between

foils to create a monolayer tape; creep and superplastic forming in a die; and spraying metal

plasmas on collimated fibers followed by hot pressing.

Superplastic aluminum:

Superplastic forming of metal, a process similar to vacuum forming of plastic sheet, has been

used to form low-strength aluminum into nonstructural parts such as cash-register housings,

luggage compartments for passenger trains, and nonload-bearing aircraft components. New in

this area of technology is a superplastic-formable high-strength aluminum alloy, now

available for structural applications and designated 7475-02. Strength of alloy 7475 is in the

range of aerospace alloy 7075, which requires conventional forming operations. Although

initial cost of 7475 is higher, finished part cost is usually lower than that of 7075 because of

the savings involved in the simplified design/assembly.

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Aluminium alloys used for Spacecraft Shuttle:

is a reusable launch system and orbital spacecraft operated by the U.S. National Aeronautics

and Space Administration (NASA) for human spaceflight missions. The system combines

rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons. The first of

four orbital test flights occurred in 1981 leading to operational flights beginning in 1982, all

launched from the Kennedy Space Center, Florida. The system is scheduled to be retired from

service in 2011 after 135 launches.Major missions have included launching numerous

satellites and interplanetary probes, conducting space science experiments, and servicing and

construction of space stations. Five space-worthy orbiters were built—two have been

destroyed and one has been retired, leaving two currently in service.

It has been used for orbital space missions by NASA, the U.S. Department of Defense, the

European Space Agency, Japan, and Germany.[3][4] The United States funded STS

development and shuttle operations except for Spacelab D1 and D2 — sponsored by West

Germany and reunified Germany respectively.In addition, SL-J was partially funded by

Japan.

At launch, the Space Shuttle consists of the shuttle stack, which includes a dark orange-

colored external tank (ET), two white, slender Solid Rocket Boosters (SRBs); and the Orbiter

Vehicle (OV), which contains the crew and payload. Payloads can be launched into higher

orbits with either of two different booster stages developed for the STS (single-stage Payload

Assist Module or two-stage Inertial Upper Stage). The Space Shuttle is stacked in the Vehicle

Assembly Building and the stack mounted on a mobile launch platform held down by four

explosive bolts on each SRB which are detonated at launch.

The shuttle stack launches vertically like a conventional rocket. It lifts off under the power of

its two SRBs and three main engines, which are fueled by liquid hydrogen and liquid oxygen

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from the external tank. The Space Shuttle has a two-stage ascent. The SRBs provide

additional thrust during liftoff and first-stage flight. About two minutes after liftoff, explosive

bolts are fired, releasing the SRBs, which then parachute into the ocean, to be retrieved by

ships for refurbishment and reuse. The shuttle orbiter and external tank continue to ascend on

an increasingly horizontal flight path under power from its main engines. Upon reaching

17,500 mph (7.8 km/s), necessary for low Earth orbit, the main engines are shut down. The

external tank is then jettisoned to burn up in the atmosphere. It is, however, possible for the

external tank to be re-used in orbit.[12] After jettisoning the external tank, the orbital

maneuvering system (OMS) engines may be used to adjust the orbit.

The orbiter carries astronauts and payload such as satellites or space station parts into low

earth orbit, into the Earth's upper atmosphere or thermosphere. Usually, five to seven crew

members ride in the orbiter. Two crew members, the commander and pilot, are sufficient for

a minimal flight, as in the first four "test" flights, STS-1 through STS-4. A typical payload

capacity is about 22,700 kilograms (50,000 lb), but can be raised depending on the choice of

launch configuration. The orbiter carries the payload in a large cargo bay with doors that

open along the length of its top, a feature which makes the Space Shuttle unique among

present spacecraft. This feature made possible the deployment of large satellites such as the

Hubble Space Telescope, and also the capture and return of large payloads back to Earth.

When the orbiter's space mission is complete, it fires its OMS thrusters to drop out of orbit

and re-enter the lower atmosphere. During descent, the orbiter passes through different layers

of the atmosphere and decelerates from hypersonic speed primarily by aerobraking. In the

lower atmosphere and landing phase, it is more like a glider but with reaction control system

(RCS) thrusters and fly-by wire-controlled hydraulically-actuated flight surfaces controlling

its descent. It then makes a landing on a long runway as a spaceplane. The aerodynamic

shape is a compromise between the demands of radically different speeds and air pressures

during re-entry, hypersonic flight, and subsonic atmospheric flight. As a result, the orbiter has

a relatively high sink rate at low altitudes, and it transitions during re-entry from using RCS

thrusters at very high altitudes to flight surfaces in the lower atmosphere.

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Properties of Aluminium Alloys:

A unique combination of properties makes aluminum one of our most versatile engineering

and construction materials. A mere recital of its characteristics is impressive. It is light in

mass, yet some of its alloys have strengths greater than that of structural steel.

It has high resistance to corrosion under the majority of service conditions, and no colored

salts are formed to stain adjacent surfaces or discolor products with which it comes into

contact, such as fabrics in the textile industry and solutions in chemical equipment. It has no

toxic reaction. It has good electrical and thermal conductivities and high reflectivity to both

heat and light. The metal can easily be worked into any form and readily accepts a wide

variety of surface finishes.

The mass of aluminum is roughly 35 percent that of iron and 30 percent that of copper.

Commercially pure aluminum has a tensile strength of about 90 MPa. Thus its usefulness as

a structural material in this form is somewhat limited. By working the metal, as by cold

rolling, its strength can be approximately doubled. Much larger increases in strength can be

obtained by alloying aluminum with small percentages of one or more other elements such

as manganese, silicon, copper, magnesium or zinc.

Like pure aluminum, the alloys are also made stronger by cold working. Some of the alloys

are further strengthened and hardened by heat treatments so that today aluminum alloys

having tensile strengths approaching 700 MPa are available.

A wide variety of mechanical characteristics, or tempers, are available in aluminum alloys

through various combinations of cold work and heat treatment. In specifying the temper for

any given product, the fabricating process and the amount of cold work to which it will

subject the metal should be kept in mind.

Aluminum and its alloys lose part of their strength at elevated temperatures, although some

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alloys retain good strength at temperatures from 200 to 260°C. At subzero temperatures,

however, their strength increases without loss of ductility, so aluminum is a particularly

useful metal for low-temperature applications.

When aluminum surfaces are exposed to the atmosphere, a thin invisible oxide skin forms

immediately, which protects the metal from further oxidation. This self-protecting

characteristic gives aluminum its high resistance to corrosion. Unless exposed to some

substance or condition that destroys this protective oxide coating, the metal remains fully

protected against corrosion. Aluminum is highly resistant to weathering, even in industrial

atmospheres that often corrode other metals. It is also corrosion resistant to many acids.

Alkalis are among the few sub stances that attack the oxide skin and therefore are corrosive

to aluminum.

Some alloys are less resistant to corrosion than others, particularly certain high-strength

alloys. Such alloys in some forms can be effectively protected from the majority of corrosive

influences, however, by cladding the exposed surface or surfaces with a thin layer of either

pure aluminum or one of the more highly corrosion-resistant alloys.

A word of caution should be mentioned in connection with the corrosion-resistant

characteristics of aluminum. Direct contacts with certain other metals should be avoided in

the presence of an electrolyte; otherwise galvanic corrosion of the aluminum may take place

in the vicinity of the contact area. Where other metals must be fastened to aluminum, the use

of a bituminous paint coating or insulating tape is recommended.

The fact that aluminum is nontoxic was discovered in the early days of the industry. It is this

characteristic that permits the metal to be used in cooking utensils without any harmful effect

on the body, and today we find also a great deal of aluminum equipment in use by food

processing industries. The same characteristic permits aluminum foil wrapping to be used

safely in direct contact with food products.

Aluminum is one of the two common metals having an electrical conductivity high enough

for use as an electric conductor. The conductivity of electric conductor grade (EN AW1350

EN 573-3) is about 62 ICAS.

The high thermal conductivity of aluminum came prominently into play in the very first

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large-scale commercial application of the metal in cooking utensils. This characteristic is

important wherever the transfer of thermal energy from one medium to another is involved,

either heating or cooling. Thus aluminum heat exchangers are commonly used in the food,

chemical, petroleum, aircraft and other industries. Aluminum is also an excellent reflector of

radiant energy through the entire range of wavelengths, from ultraviolet, through the visible

spectrum to infrared and heat waves, as well as electromagnetic waves of radio and radar.

Aluminum has a light reflectivity of over 80 percent, which has led to its wide use in lighting

fixtures. Aluminum roofing reflects a high percentage of the sun’s heat, so that buildings

roofed with this material are cooler in summer.

The ease with which aluminum may be fabricated into any form is one of its most important

assets. Often it can compete successfully with cheaper materials having a lower degree of

workability. The metal can be cast by any method known to foundry men; it can be rolled to

any desired thickness down to foil thinner than paper; aluminum sheet can be stamped,

drawn, spun or roll-formed. The metal also may be hammered or forged. Aluminum wire,

drawn from rolled rod, may be stranded into cable of any desired size and type. There is

almost no limit to the different profiles in which the metal may be extruded.

The ease and speed with which aluminum may be machined is one of the important factors

contributing to the low cost of finished aluminum parts. The metal may be turned, milled,

bored, or machined in other manners at the maximum speeds of which the majority of

machines are capable. Another advantage of its flexible machining characteristics is that

aluminum rod and bar may readily be employed in the high speed manufacture of parts by

automatic screw machines.

Almost any method of joining is applicable to aluminum: riveting, welding, brazing or

soldering. A wide variety of mechanical aluminum fasteners simplifies the assembly of many

products. Adhesive bonding of aluminum parts is widely employed, particularly in joining

aircraft components.

For the majority of applications, aluminum needs no protective coating. Mechanical finishes

such as polishing, sand blasting or wire brushing meet the majority of needs. In many

instances, the surface finish supplied is entirely adequate without further finishing. Where

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the plain aluminum surface does not suffice, or where additional protection is required, any

of a wide variety of surface finishes may be applied. Chemical, electrochemical and paint

finishes are all used. Many colors are available in both chemical and electrochemical

finishes. If paint, lacquer or enamel is used, any color possible with these finishes may be

applied. Vitreous enamels have been developed for aluminum, and the metal may also be

electroplated.

Aluminum sheet, because of its superior corrosion resistance and smooth continuous surface,

is an excellent base for the high quality paints used in producing painted sheet. The chemical

pretreatment plus the application of high quality thermally cured paint assures a finish that

will exhibit no cracking, blistering, or peeling.

Attractive appearance together with high resistance to weathering and low maintenance

requirements have led to extensive use in buildings of all types. High reflectivity, excellent

weathering characteristics, and light weight are all important in roofing materials. Light

weight contributes to low handling and shipping costs, whatever the application.

Many applications require the extreme versatility that only aluminum has. Almost daily its

unique combination of properties is being put to work in new ways.

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References

http://www.mmat.ubc.ca/courses/mmat380/lectures/2004/Lecture%2016-Aluminum(Complete).pdfhttp://www.eaa.net/education/TALAT/lectures/1255.pdfhttp://www.ccm.udel.edu/Personnel/homepage/class_web/ Lecture%20Notes/2004/AskelandPhuleNotes-CH13Printable.ppthttp://www.aluminum.org/http://www. aluminium .org/ http://www.eaa.net/education/TALAT/lectures/1255.pdfhttp://www.cmse.ed.ac.uk/MSE3/Topics/MSE3-nonferrous.pdfhttp://www.eaa.net/education/TALAT/lectures/1205.pdf

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