Approximate Cost Per Unit Volume for Wrought
Metals and Plastics Relative to Carbon Steel
Gold 60000 Mg Alloys 2-4
Silver 600 Al Alloys 2-3
Mo Alloys 200-250 High Strength Steels 1.4
Nickel 35 Gray Cast Iron 1.2
Ti Alloys 20-40 Carbon Steel 1
Cu Alloys 5-6 Nylons, silicon rubber 1.1-2
Zinc Alloys 1.5-3.5 Plastics/Elastomers 0.2-1
Stainless Steels 2-9 Fiber Composites 40-80
Serope Kalpakjian. Manufacturing Engineering and Technology, 3rd Edition. Addison-Wesley Publishing Co. 1995.
Electrolytic Cell Used to Produce Aluminum
99.5% to 99.9% pure aluminum (iron and silicon chief impurities)
(Oxygen released at
anode attacking carbon)
(Dissoved Al2O3)
(Deposited in
liquid state on
lining; sinks to
bottom)
Al is most abundant element in Earth’s core, but in combined form
which must be processed to produce Al 2O3 ($$)
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
(Courtesy of Aluminum Company of America).
Wrought Aluminum Alloy Groups
4 Digits: 1st is alloy group
2nd indicates modification of base alloy
Last two identify alloy or purity
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Cast Aluminum Alloy Groups
4 Digits: 1st is alloy group
2nd two identify Al alloy or impurity
Last is product form (casting/ingot)
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Typical Properties of Aluminum Alloys
Pure
Mn
Mg
Mg
Cu
Mg, Si
Zn
Richard A. Flinn and Paul K. Trojan. Engineering Materials and Their Applications, 4th Edition. Houghton Mifflin Co. 1990.
Typical Properties of Aluminum Alloys
Richard A. Flinn and Paul K. Trojan. Engineering Materials and Their Applications, 4th Edition. Houghton Mifflin Co. 1990.
Temper Designations
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
(Courtesy of Aluminum Company of America).
Temper Designations
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
(Courtesy of Aluminum Company of America).
Temper Designation Example
The specification for the T6 condition reads “solution heat treated plus
artificially aged.” What is the time-temperature chart for this, for a 6% Cu-
94% Al alloy, assuming the starting material is slow-cooled from 900F?
A) Solution heat treat at 525C
to supersaturate ? ? ?
L
A
B) Quench to keep ?
B supersaturated with Cu
C
? +?
C) Ages at ~170C to produce
fine precipitate of ?
Wt. % Al
Additional Temper Designations
See MIL-HDBK-5, Table 3.1.2
Compositions, Mechanical Properties and Typical
Applications of Eight Common Aluminum Alloys
William D. Callister, Jr. Materials Science and Engineering, An Introduction. John Wiley & Sons, Inc. 1985.
Stress Corrosion Cracking
Mildly Corrosive Environment
Small Concentration of Harmful Elements
Localized, One or More Cracks Propagate
Residual Stress Often Sufficient for Failure
(multiple graphic examples, tabular in MIL-
HDBK-5E table 3.1.2.3.1a
Weldability
Welding generally causes a loss in mechanical properties,
particularly for precipitation hardened alloys
(e.g. MIL-HDBK-5E Table 3.1.3.4a)
Commercially Pure Aluminum
(99.0% to 99.7% Aluminum)
Relatively pure Al matrix
Iron and Silicon insoluble
constituents
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Commercially Pure Aluminum
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Strain Hardening/Strain Softening
Recall For ductile materials with no prior work hardening, true s-e behavior
follows power law: ? = K?n (strain hardening eqn)
where K = strength coeff., n is strain hardening exponent
• Strain hardening occurs when n>0.2
• Strain softening occurs when n<0.1
Typical Values for K and n at Room Temperature
Aluminum K(Mpa) n
1100-O 180 0.20
2024-T4 690 0.16
6061-O 205 0.20
6061-T6 410 0.05
7075-O 400 0.17
Brass (70-30 annealed) 900 0.49
Cobalt alloy 2070 0.50
Copper, annealed 315 0.54
Serope Kalpakjian. Manufacturing Engineering and Technology, 3rd Edition. Addison-Wesley Publishing Co. 1995.
Portions of Aluminum Rich Phase Diagrams
Richard A. Flinn and Paul K. Trojan. Engineering Materials and
Their Applications, 4th Edition. Houghton Mifflin Co. 1990.
Aluminum-Magnesium Phase Diagram
5000 Series
Aluminum
>7% Mg for
precipitation
hardening
Richard A. Flinn and Paul K. Trojan. Engineering Materials and Their Applications, 4th Edition. Houghton Mifflin Co. 1990.
Typical Mechanical Properties of Wrought Non-
Heat-Treatable Aluminum-Magnesium Alloys
Wide range
of strength
Good
forming
and
welding
Corrosion
resistant
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Typical Mechanical Properties of Wrought Non-
Heat-Treatable Aluminum-Magnesium Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Aluminum-Copper Phase Diagram
Copper is one of the most important alloy elements (precipitation hardening)
5.65% Cu
Richard A. Flinn and Paul K. Trojan. Engineering Materials and Their Applications, 4th Edition. Houghton Mifflin Co. 1990.
Chemical Compositions and Applications of
Aluminum-Copper Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Binary Aluminum-Copper Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Microstructures of Binary Aluminum-Copper Alloys
Lower Temp (<130C), Impede dislocations
(Increased hardening, Decreased ductility) Overaging
(decreased hardness)
Cu content increases in zones
(incr. hardening, decr. ductility)
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Commercial Wrought Aluminum-Copper Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Typical Mechanical Properties of Heat-Treatable
Aluminum-Copper Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Chemical Compositions and Applications of
Aluminum-Copper-Magnesium Alloys
Addition of Mg to Al-Cu accelerates and intensifies precipitation hardening
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Typical Mechanical Properties of Wrought Heat-
Treatable Aluminum-Copper-Magnesium Alloys
Sensitive to solution heat treatment temperature (control of precipitates)
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Aluminum-Copper-Magnesium Alloys
A B C
Precipitate nucleated at Cold working increases # of Further cold working, refined
dislocations dislocations, increasing density and higher density
of precipitate laths precipitate
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
2024 Alloy
MIL-HDBK-5E Section 3.2.3
• Material specifications
• Design mechanical and physical properties
• Cryogenic applications
• Cladding
Chemical Compositions and Applications of
Aluminum-Magnesium-Silicon Alloys
Mg and Si form
MgSi2 precipitate
Mn or Cr increases
strength, grain size
control
Cu increases
strength, but >0.5%
reduces corrosion
resistance
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Typical Mechanical Properties of Wrought Heat-
treatable Aluminum-Magnesium-Silicon Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Aluminum-Magnesium-Silicon Alloys
Significant strengthening
due to increased energy
required to break MgSi2
bonds (as dislocations
pass through precipitates)
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Aluminum-Magnesium-Silicon Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Chemical Compositions and Applications of Aluminum-Zinc-
Magnesium and Aluminum-Zinc-Copper Alloys
Highest strength Aluminum alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Typical Mechanical Properties of Wrought Heat-Treatable
Aluminum-Zinc-Magnesium and Aluminum-Zinc-
Magnesium-Copper Alloys
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
Aluminum-Zinc-Magnesium-Copper Alloys
High density of small somewhat Wide precipitate free zones at grain
spherical chromium rich precipitates boundaries; Increased dislocation
(Ftu~77ksi, Fty~66ksi) mobility (Ftu~64ksi, Fty~54ksi)
William F. Smith. Structure and Properties of Engineering Alloys. McGraw-Hill Publishing Co. 1981.
7075 Alloy
MIL-HDBK-5E Section 3.7.4
• Material specifications
• Design mechanical and physical properties
Endurance Strength
Endurance
Strength
Serope Kalpakjian. Manufacturing Engineering and Technology, 3rd Edition. Addison-Wesley Publishing Co. 1995.
