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Solid Solution and Precipitation Hardening in Aluminum Alloys, Slides of Classical Mechanics

Information on solid solution and precipitation hardening in aluminum alloys. It explains the process of impurity atoms going into solid solutions and the interaction between strain fields, leading to dislocation movement restriction. The document also covers dispersion strengthening through the introduction of second phases and the effect of particle size on strengthening.

Typology: Slides

2012/2013

Uploaded on 04/16/2013

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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% Docsity.com 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 Docsity.com 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) Docsity.com 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 Docsity.com
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