Download Solid Solution and Precipitation Hardening in Aluminum Alloys and more Slides Classical Mechanics in PDF only on Docsity! Dispersion and Solution Hardening Docsity.com Solid Solution Hardening - Impurity atoms go into either substitutional or interstitial solid solution. Lattice strain field interacts between dislocations and these impurity atoms result, and consequently, dislocation movement is restricted. - The strain (or stress) field “roughen” the lattice structure and hinder the dislocation movement. Docsity.com Solid Solution Hardening Example — Al Alloys
Temperature °C
Atomic Percent Magnesium
lo 20 30 40 50 60 70 80 90 100
700 : ni LL, i nl ia 1 1 i
0,
leso.452°C 480°C]
e004 b
500 t
(al) °
AgMay (ug)
4004 b
Es \
300-4 b
AlMgz
200 L
100) + 1 1 r 7 T r 7 r
0 10 20 30 40 30 60 70 80 90 100
Al Weight Percent Magnesium Mg
1.8%
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5000 series Aluminum Alloys (Al-Mg) (1) Hold at 450C (Solution Heat Treatment) (2) Cool moderately quickly to room temperature Docsity.com Solid Solution Hardening — Al Alloys
Table 10.3 Yield strengths of 5000 series (Al-Mg) alloys
Alloy wit Mg 0,({MPa}
(annealed condition}
5005 0.8 40
5050 1.6 55
5052 2.5 90
5454 27 120 supersaturated
5083 45 145
5456 5.1 160
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Precipitate or Dispersion Hardening -Small particles 2/32/12/1)(6 εσ f b rG≈∆ Strengthening Particle Radius Strengthening effect can be estimated as: G – Shear Modulus r – Particle radius b – Burgers vector f – volume fraction of particles ε - strain field factor Docsity.com Precipitate or Dispersion Hardening - Big Particles Dislocation Bypass by the Orowan Bowing Mechanism: Docsity.com Precipitate or Dispersion Hardening - Big Particles The stress required to bypass in this manner is given by the line tension when the dislocation is bowing at the maximum curvature – Depends then on the distance between particles (L): Gb L τ∆ ≈ ∆τ - Shear strength increase G – Shear Modulus b – Burgers vector L – Particle spacing Docsity.com Age (Precipitation) Hardening http://www.doitpoms.ac.uk/miclib/pds.swf?targetFrame=Al-Cu Docsity.com Age (Precipitation) Hardening Room temperature microstructures in Al-4%Cu alloy. (a) slow cooling; (b) moderately fast cooling Docsity.com Age (Precipitation) Hardening
TEC)
200;—- [7 Quench
100;— |
Solution
treat
All
supersaturated
\ a
Lb All stable o
\ Tt
LP
! Aue \
1 | 1 Ll | 1 l
0
1074 10°97 10°? 1077 1 10’) 10? 10? 108
Time (bh)
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Commercially Pure Aluminum – 1000 series Microstructure 1100-0 sheet, cold-rolled and annealed. FeAl3 (black) particles. Docsity.com Commercially Pure Aluminum — 1000 series
Table 5-5 Typical mechanical properties of commercially pure aluminumt
Tensile Tensile yield Elon- Hard- Shear Fatigue
strength, strength,f gation, ness,§ strength, limi.)
Alloy Temper psi psi % in 2 in Bhn psi psi
1199 oO 6,500 1,500 50
H18 17,000 16,000 $
1180 °o 9,000 3,000 45
H18 18,000 £7,000 5
1060 °o 10,000 4,000 43 19 7,000 3000
HI4 14,000 13,000 12 26 9,000 5000
HI8 19,000 18,000 6 35 11,000 6500
EC 0 12,000 4,000 234t 8,000
HI4 16,000 £4,000 10,000
HI9 27,000 24,000 2.5tt 15,000
1145 °o 11,000 5,000 40 8,000
HI8 21,000 17,000 5 12,000
1100 oO 13,000 5,000 35 23 9,000 5000
HI4 18,000 17,000 9 "32 11,000 7000
HI8 24,000 22,000 5 4 13,000 9000
3 Docsity.com
Al-Cu-Mg Alloys — 2000 series
Table 5-12 Chemical compositions and applications of
aluminum-copper-magnesium alloys}
Alloy %Cu %Mg %Mn %Si %Ni %Other Applications
2014 44 «05 «(08 ~=—(08 Truck frames, aircraft structures
2017 40 «06 «= 0705 Screw-machine products, fittings
2018 4.0 © 07 20 Aircraft engine cylinder heads and pistons
2024 44 «15 (06 Truck wheels, screw-machine products,
aircraft structures
2218 40 «15 20 Jet engine impellers and compressor
rings, aircraft engine cylinder heads
and pistons
218 23 16 0.18 Si, 1.ONi, Aircraft engines, temperatures to 238°C
1.1 Fe, 0.07 Ti
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