© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein MATSE 259 Lecture 2: Introduction to Aluminum Alloys Christopher L. Muhlstein, Ph.D.

Department of Materials Science and Engineering The Pennsylvania State University University Park, PA The contents of this lecture are protected under U.S. copyright law and should not be duplicated or redistributed for commercial purposes.

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© C. Muhlstein, 2007 Last Lecture • Fundamentals of materials science and engineering • Classes of materials properties • Three classes of materials • Steel nomenclature MATSE 259 Spring 2007, C. Muhlstein 2

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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 3

© C. Muhlstein, 2007 Al Structural Alloys MATSE 259 Spring 2007, C. Muhlstein Lotus Elise 190 hp 1984 lbs 0-60 mph - 4.9 sec top speed - 150 mph 27 mpg highway $46K 4

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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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© C. Muhlstein, 2007 Which “aluminum” is it?

MATSE 259 Spring 2007, C. Muhlstein 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 6

© C. Muhlstein, 2007 Aluminum Alloy Overview MATSE 259 Spring 2007, C. Muhlstein • 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 7

© C. Muhlstein, 2007 Aluminum Alloy Nomenclature MATSE 259 Spring 2007, C. Muhlstein • 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) 8

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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 9

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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) 10

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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 11

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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 12

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein • Amorphous materials • Single crystal materials • Polycrystalline materials • Grain boundaries • Isotropic and anisotropic properties Material Structure Small crystalline nuclei Growth of crystallites Solidified Optical micrograph Schematic of stages of solidification of a polycrystalline material; the square grids depict unit cells Callister,

Materials Science and Engineering: An Introduction

(2003) 13

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein 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) 14

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein Microstructural Evaluation (Optical) • Optical Microscopy – Grind – Polish – Etch/stain/anodize – Image 15

© C. Muhlstein, 2007 Etchants Reveal Microstructure MATSE 259 Spring 2007, C. Muhlstein Polished Gray Iron Polished and Etched Gray Iron 16

© C. Muhlstein, 2007 MATSE 259 Spring 2007, C. Muhlstein Wrought Aluminum Microstructures 10% Reduction 80% Reduction 40% Reduction 5457-O plate, Barker’s reagent ASM,

Metals Handbook Volume 9

(1995) 17

© C. Muhlstein, 2007 Steel Microstructures MATSE 259 Spring 2007, C. Muhlstein Pearlite Martensite Tempered Martensite Spheroidite Callister,

Materials Science and Engineering: An Introduction

(2003) 18