Al alloys alia

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Al alloys alia

  1. 1. ALUMINIUM ALLOYSBY: Alia Ahmed diaaProduction Engineering
  2. 2. Al Alloys And Temp. Designationback
  3. 3. Designation: Wrought Al AlloysNon-heat-treatable alloys• 1xxx series (Super-purity and commercial-purity aluminium)• 3xxx series (Al-Mn and Al-Mn-Mg alloys)• 5xxx series (Al-Mg alloys)• 8xxx series (Miscellaneous alloys)Heat-treatable alloys• 2xxx series (Al-Cu and Al-Cu-Mg alloys)• 6xxx series (Al-Mg-Si alloys)• 7xxx series (Al-Zn-Mg and Al-Zn-Mg-Cu alloys)
  4. 4. Al-Cu alloys (2xxx series)• Cu (Tm = 1085oC, FCC structure)• Good solubility up to 5.65% at 548oC (eutectic).• Eutectic reaction gives :o α phase (5.65%Cu) – ductile+o θ phase (CuAl2-52.75%Cu) – brittle.• Precipitation hardening – by forming θ phase inα matrix, gives high strength and toughness.
  5. 5. Equilibrium phase diagram Al-Cu• Eutectic phase:consists of alternate lamella structureof α and θ phases,resembling pearlite in carbonsteels, which give high strength butbrittle.• Hypoeutectic:> 5% Cu, cooling is in equilibrium,grain boundaries of α phasesurrounded by (α+θ ) eutectic phase -reduced toughness.< 5% Cu, α phase in some casessurrounded by θ phase.• Hypereutectic• Cu 33%, too brittle due tohigh amount of θ phase.Al-Cu alloys (2xxx series)
  6. 6. Properties & ApplicationsProjetar tabelas para um novo banco de dadosFuel TanksProperties:• High strength (2119: σTS 505 MPa).• Good creep strength at high temp.• High toughness at cryogenic temp.• Good machinability.Welding wire
  7. 7. • Equilibrium cooling gives α + θ (CuAl2) - non-coherent precipitates with the matrix(starting at A). But Quenching give supersaturated solid solution (α’ phase) - higheramount of Cu can be dissolved in the matrix.•Coherent θ ’ changes to non-coherent precipitates θ with increasing ageing time (tryto get back to equilibrium) less strength due to no distortion within the lattice. (Overaging)Age- Hardening Mechanism in Al - Cu
  8. 8. Al-Cu-Mg alloys (2xxx series)Applications:• pistons, rivets for aircraftconstructions• Miner amount of Mg (0.2%) modifies the precipitationprocess, resulting in greater age-hardening.Properties:• High strength (2024: σTS 520 MPa).• high toughness.2024-T4 (solutionheat treated) plateshowingredistribution ofconstituents2024 heatedingot showingsolubleAl2CuMg.Airplane structureAluminum pistons and devices forthermal shock used in airplanes
  9. 9. Designations of Cast Aluminum Alloys1xx.x series• Second two digits indicatethe minimum percentage ofAl, Ex: 150.x 99.50% Al.• Last digit (after decimalpoint) indicates product forms.1 = casting, 2 = ingot2xx.x to 9xx.x series• Second two digits identifythe different aluminum alloys.• Last digit (after decimalpoint) indicates product forms
  10. 10. Al-Cu alloyProjetar tabelas para um novo banco de dadosAerospacehousing(201.0)• Strength and hardness - at T up to 250oC –a combination of precipitation hardening together with dispersionhardening by intermetallic compounds.• Strength is higher than other cast Al alloys and comparable to wrought Alalloys.Note: Have casting problem with hot-tearingProperties:σy 345-480 MPa and σTS 415- 550MPa due to high response to ageingApplications:Elevated temperature applications.Ex; diesel engine pistonsair-cooled cylinder heads foraircraft.Flywheel housing(295.0)

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