Ni and Al Alloys

7/27/2019 Ni and Al Alloys

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Ni alloys


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Nickel-base alloy chart showing alloys containing

varying amounts of nickel and iron.

Chromium contents are constant at approximately 18 to 20%.


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Nominal compositions of nickels and nickel alloys


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Wasp alloy: 19.5% Cr, 13.5% Co, 1.3% Al, 3% Ti, 0.06% Zr, 0.08% C, Ni balance

Nimonics: 20% Cr, 20% Co, 0.5% Al, 6% Mo, 0.15% C, Ni balance

Monel: Ni-CuInconel: Ni-(14-17%) Cr- (6-10%) Fe

Nimonics: Ni-Cr-Co

Hastealloys: Ni-Mo-Fe


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h

Effect of heat treatment temp (HT:3 hour) for cold

drawn Monel 400 rod


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Strengthening of Ni

1. Solid Solution Hardening (Co, Cr, Fe, Mo, W, V, Ti, Al)

2. Precipitation Hardening : Ni3(Al,Ti)


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Cu-Ni Phase Diagram


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Co-Ni Phase Diagram


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Ni-Cr Phase Diagram


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Fe-Ni Phase Diagram


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Al-Ni Phase Diagram


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Ti-Ni Phase Diagram


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Heat treatment of Ni alloys

Annealing: A heat treatment designedto produce a recrystallizedgrain structure and softening in workhardenedalloys. Annealing

usually requires temperatures between 705 and 1205 C (1300

and 2200 F), depending on alloy composition and degree of work

hardening

Solution annealing: A high-temperature anneal (1150 to 1315 C, or

2100 to 2400 F) of certain nickelalloys to put carbides in solid

solution and produce a coarse grain size for enhanced stress-rupture

properties


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Heat treatment of Ni alloys

Stress relieving:A heat treatment used to remove or reduce stresses

in work-hardened non-agehardenable alloys without producing arecrystallized grain structure. Stress-relieving temperatures for

nickel and nickel alloys range from 425 to 870 C (800 to 1600 F),

depending on alloy composition and degree of work hardening

Solution treating:A high-temperature heat treatment designed toput age-hardening constituents into solid solution. Normally applied

to age-hardenable materials before the aging treatment

Age hardening (precipitation hardening):A treatment performedat intermediate temperatures (425 to 870 C, or 800 to 1600 F) on

certain alloys to develop maximum strength by precipitation of a

dispersed phase throughout the matrix


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Assignment

1. Shape Memory Alloys

2. Role of alloying elements on corrosion of Ni based alloys

3. Role of Co in Ni alloys.


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Al alloys


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Hardness and strength of Al as functions of purity


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Al alloy designation system


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Wrought Aluminum and Aluminum Alloy

Designation System


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Cast Aluminum and Aluminum Alloy Designation

System


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Basic Temper DesignationsF, As-Fabricated. This is applied to products shaped by cold

working, hot working, or casting processes in which no

special control over thermal conditions or strain hardening is employed.For wrought products, there are no mechanical property limits.

O, Annealed. O applies to wrought products that are annealed to

obtain lowest-strength temper and to cast products that

are annealed to improve ductility and dimensional stability. The O may

be followed by a digit other than zero.

H, Strain-Hardened (Wrought Products Only). This indicates

products that have been strengthened by strainhardening, with or without supplementary thermal treatment to produce

some reduction in strength. The H is always followed by two or more

digits.


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W, Solution Heat-Treated. This is an unstable temper applicable only

to alloys whose strength naturally

(spontaneously) changes at room temperature over a duration of monthsor even years after solution heat treatment. The designation is specific

only when the period of natural aging is indicated (for example,W 12 h).

T, Solution Heat-Treated. This applies to alloys whose strength is

stable within a few weeks of solution heat

treatment. The T is always followed by one or more digits.

di ib i f j l i d


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ercentage distribution of major aluminum products

Standardized Products

Engineered Products

W h Al ll i i


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1xxx Series. Aluminum of 99.00% or higher purity has many

applications, especial ly in the electr ical and chemicalfields.

These grades of aluminum are characterized by excellent corrosion

resistance, high thermal and electrical conductivities, low

mechanical properties, and excellent workability. Moderate increases

in strength may be obtained by strain hardening. Iron and silicon are the

major impurities.

Typical uses include chemical equipment, reflectors, heat exchangers,

electrical conductors and capacitors, packaging foil, architecturalapplications, and decorative trim.

Wrought Al alloy compositions

P ti f l i bi h di


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Portion of aluminum-copper binary phase diagram2xxx Series


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2xxx Ser ies. Copper is the principal alloying element in 2xxx series

alloys, often with magnesium as a secondaryaddition.

These alloys require solution heat treatment to obtain optimumproperties; in the solution heat-treated condition, mechanical properties

are similar to, and sometimes exceed, those of low-carbon steel.

In some instances, precipitation heat treatment (aging) is employed to

further increase mechanical properties. This treatment increases yield

strength, with attendant loss in elongation; its effect on tensile strength is

not as great.

The alloys in the 2xxx series do not have as good corrosion resistance as

most other aluminum alloys, and under certain conditions they may be

subject to intergranular corrosion.

Therefore, these alloys in the form of sheet usually are clad with a

high-purity aluminum or with a magnesium-silicon alloy of the 6xxx

series, which provides galvanic protection of the core material and thus

greatly increases resistance to corrosion.


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Alloys in the 2xxx series are particularly well suited for parts and

structures requir ing high strength-to-weight ratiosand are commonly

used to make truck and aircraft wheels, truck suspension parts, and wing

skins, and structural parts and those parts requiring good strength attemperatures up to 150 C (300 F). Except for alloy 2219, these alloys

have limited weldability, but some alloys in this series have superior

machinability.


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3xxx Series. Manganese is the major alloying element of 3xxx ser ies

alloys. These alloys generally are non-heat treatablebut have about20% more strength than 1xxx series alloys.

Because only a limited percentage of manganese (up to about 1.5%) can

be effectively added to aluminum, manganese is used as major elementin only a few alloys. However, three of them--3003, 3X04, and 3105--are

widely used as general-purpose alloys for moderate-strength applications

requiring good workability.

These applications include beverage cans, cooking utensils, heatexchangers, storage tanks, furniture, highway signs, roofing, siding, and

other architectural applications.


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4xxx Series. The major alloying element in 4xxx ser ies alloys is si l icon,

which can be added in sufficient quantities (up to 12%)to cause

substantial lowering of the melting range without producing brittleness.

For this reason, aluminumsilicon alloys are used in welding wire and as

brazing alloys for joining aluminum, where a lower melting range than

that of the base metal is required.

Most alloys in this series are non-heat treatable, but when used in

welding heat-treatable alloys, they will pick up some of the alloying

constituents of the latter and so respond to heat treatment to a limited

extent.

Alloy 4032 has a low coefficient of thermal expansion and high wear

resistance, and thus is well suited to production of forged engine pistons.

P ti f l i ili bi h di


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Portion of aluminum-siliconbinary phase diagram

W ht Al M (


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Wrought Al- Mg (


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Portion of Al-Mg phase diagram

Comparison of mechanical properties of Al Mg allo


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Comparison of mechanical properties of Al-Mg allo

Al-Cu alloy

Al-4 Cu-0.5 Mg

Mechanical properties of Al Mg Mn alloy


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Mechanical properties of Al-Mg-Mn alloy

Cast Al Mg alloy compositions 5XX X


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Cast Al- Mg alloy compositions-5XX.X

Alloy 214 (3.8% Mg), 218 (8% Mg): dairy and food handling

equipment, fittings for marine, chemical and sewage, air craft brake shoes

Alloy 220 (10% Mg) : agehardenable

-exhibits highest mech. Properties than any Al casting alloys

-the casting properties of these alloys are poor

Typical Alloy Uses:

Wrought Al Si Mg alloy compositions 6XXX


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Wrought Al- Si Mg alloy compositions-6XXX

Mg and Si combine to form Mg2Si compound.

Mg2Si (1.85 % at 580o

C) forms eutectic system with Al

Heat treatable alloys (artificial ageing-results in high strength)

Characteristics: excellent corrosion resistance and good workability

than other heat treatable alloys

Alloy 6053, 6061, 6063 are few examples

Applications: air craft landing mats, furniture, vacuum-cleaner tubing,

bridge railings and architectural applications

Typical Alloy Uses:


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Examples: Alloy 355, 356, 360

Properties: good castability, strength and corrosion resistance

Heat treatable:properties comparable with Al-Cu alloys

Uses: Aircraft applications, machine-tool parts, general purpose castings

Cast Al- SiMg alloy compositions-3XX.X

Wrought Al Zn alloy compositions 7XXX


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Wrought Al- Zn alloy compositions-7XXX

Solubility of Zn in Al 32.4 at 277oC.

Wrought alloys contain Zn, Mg, Cu with small addition of Mn and Cr

Alloy 7075 (5.5% Zn, 2.5 % Mg, 1.5 % Cu)

Alloy 7079(4.3% Zn, 3.3 % Mg, 0.6% Cu)

Alloy 7178(6.8% Zn, 2.7 % Mg, 2.0 % Cu):Highest strength in Al alloy

Applications: Aircraft structural parts (where high strength and high

Corrosion resistance required)

Corrosion: They are prone to stress corrosion

Remedy: Cr addition, heat treatment

Portion of Al Zn phase diagram


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Portion of Al-Zn phase diagram

Mechanical properties of Al 1 5 Cu (1&3) Mg alloy


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Mechanical properties of Al-1.5 Cu-(1&3) Mg alloy

Wrought Al- Zn alloy compositions-6XX X


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Wrought Al- Zn alloy compositions-6XX.X

Properties: fair casting characteristics, good corrosion resistanceGood machinability

Applications: Aircraft fittings, turret housings, radio equipment

Equilibrium solubility of alloying elements in Al


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Equilibrium solubility of alloying elements in Al

Natural aging curves for three solution heat-


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Natural aging curves for three solution heat-

treated wrought Al alloys

Al Li alloy


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Al- Li alloy

ALUMINUM-LITHIUM ALLOYS have been developed primarily to

reduce the weight of aircraft and aerospace structures

Properties: low density, high specific modulus, and excellent fatigue

and cryogenic toughness properties

Uses: cryogenic applications (for example, liquid oxygen and

hydrogen fuel tanks for aerospace vehicles).

Portion of Al-Li phase diagram


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Portion of Al-Li phase diagram

Average yield stress versus aging time for Al-Li alloy 2090


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Average yield stress versus aging time for Al Li alloy 2090

(2.4% Li, 2.4% Cu, 0.18% Zr, balance aluminum) with

various amounts of prior deformation

Documents

Ni and Al Alloys