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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
The contents of this lecture are protected under U.S. copyright law and should not be duplicated or redistributed for commercial purposes.
MATSE 259
Lecture 2: Introduction to Aluminum Alloys
Christopher L. Muhlstein, Ph.D.
Department of Materials Science and EngineeringThe Pennsylvania State University
University Park, PA
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Last Lecture
• Fundamentals of materials science and engineering
• Classes of materials properties
• Three classes of materials
• Steel nomenclature
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Lecture 2: Key Concepts and References
• Aluminum alloy nomenclature
• Introduction to phases
• Reference (Callister)– sects. 3.12, 4.3, 5.1– pps. 261-262 – chapter 6
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Al Structural Alloys
Lotus Elise 190 hp 1984 lbs 0-60 mph - 4.9 sec top speed - 150 mph 27 mpg highway $46K
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Automotive Application of Al Alloys
• Lotus versatile vehicle architecture system (VVA)
• Almost all “aluminum high pressure die-castings, stampings, and extrusions
Advanced Materials & Processes, July 2005, p 29
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Which “aluminum” is it?
1050 1145 2014 2024 2219 2618 3003 3004 3105 4032 4043 5005 5052 5083 5154 5182 5262 5652 6010 6061 6262 6463 7005 7050 7072 7075 7175 7178 7475 7229
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Aluminum Alloy Overview
• Low density (~34% of steel)
• High thermal and electrical conductivity
• Corrosion resistant in ambient air
• Low melting point (660°C)
• Modified mechanical properties via cold work, alloying, and heat treating
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Aluminum Alloy Nomenclature
• Aluminum Association Number
• 4 digit number + temper designation (letter and sometimes numbers)
• Wrought vs. cast designation– 4 digits, no punctuation (e.g. 6061)– 4 digits, decimal point between last two digits (e.g.
295.0)
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Wrought Aluminum Alloy Nomenclature
• First digit indicates alloy group– 1XXX Aluminum ≥99.00%– 2XXX Copper– 3XXX Manganese– 4XXX Silicon– 5XXX Magnesium– 6XXX Magnesium + Silicon– 7XXX Zinc– 8XXX other elements– 9XXX Unused series
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
1XXX Series Wrought Aluminum Alloys
• 10XX are unalloyed
• Last two digits give minimum aluminum percentage– 1035 contains 99.35% aluminum
• The second digit indicates control over specific impurities (e.g. silicon)
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Cast Aluminum Alloy Nomenclature
• First digit indicates alloy group– 1XX.X Aluminum >99.00%– 2XX.X Copper– 3XX.X Silicon with added copper and/or magnesium– 4XX.X Silicon– 5XX.X Magnesium– 7XX.X Zinc– 8XX.X Tin– 9XX.X Other elements
• Second two digits identify specific alloy• Last digit indicates casting (0) or ingot (1)• Letter may be appended, in some cases
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
1XX.X Series Cast Aluminum Alloys
• Second two digits indicate minimum aluminum percentage– 135.0 Aluminum is a 99.35% aluminum casting– 135.1 Aluminum is a 99.35% aluminum ingot
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Material Structure
• Amorphous materials
• Single crystal materials
• Polycrystalline materials
• Grain boundaries• Isotropic and
anisotropic properties
Schematic of stages of solidification of a polycrystalline material; the square grids depict unit cells
Small crystalline nuclei Growth of crystallites
Solidified Optical micrograph
Callister, Materials Science and Engineering: An Introduction (2003)
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Structural Materials are Complicated!
• Names?
• Crystal structure(s)?
• Microstructure?
Transmission electron micrograph of 7150-T651 Optical micrographs of various cast irons.
Callister, Materials Science and Engineering: An Introduction (2003)
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Microstructural Evaluation (Optical)
• Optical Microscopy– Grind– Polish– Etch/stain/anodize– Image
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Etchants Reveal Microstructure
Polished Gray Iron Polished and Etched Gray Iron
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Wrought Aluminum Microstructures
10% Reduction 40% Reduction
80% Reduction
5457-O plate, Barker’s reagent
ASM, Metals Handbook Volume 9 (1995)
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MATSE 259 Spring 2007, C. Muhlstein© C. Muhlstein, 2007
Steel Microstructures
Pearlite
SpheroiditeCallister, Materials Science and Engineering: An Introduction (2003)
Martensite
Tempered Martensite
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