This document provides an overview of aluminum alloys, including their chemistry, classification system, applications, manufacturing processes, heat treatments, and common defects. It discusses the major alloying elements used in aluminum like copper, manganese, silicon, magnesium, and zinc. It also summarizes the various production methods for wrought aluminum alloys like extrusion and heat treating processes like annealing, solution heat treatment, and precipitation hardening. Finally, it outlines typical casting, extrusion, forging, and heat treatment defects seen in aluminum alloys.

1. Aluminium Alloys – Overview
Naveed Akhtar

2. Contents
1. Introduction
2. Chemistry
3. Classification
4. Applications
5. Manufacturing
6. Heat treatment
7. Common Defects
8. Conclusions
2

3. Introduction Abundance
Oxygen
Aluminum Oxide / Bauxite
Silicon
Iron
All Others
3

4. Introduction Advantages
• High strength to weight ratio
• High electrical and thermal conductivity
• High reflectivity and resistance to
corrosion
• Non-toxic (ideal for packaging and cooking
material)
• Ductility-easy to cold work and fabricate
4

5. History Aluminum Production
• The first commercial batch of Aluminum
was produced in 1888
• Production Capabilities Lower the Price
– Between 1888 and 1893 Aluminum dropped
from $4.86/lb to $.78/lb
5

6. • Early uses for Aluminum
– Cooking utensils
– Electrical wire and cable
– Foil
– Auto bodies
– Engine parts used by the Wright Brothers’
History Use
6

7. Chemistry Alloying Elements
Ti, B, Zr, Cr, Ni, Bi,
Pb
Cu, Mn, Mg, Si,
Zn, Fe
Principal
Alloying
Elements
Additional
Alloying
Elements
7

8. Role of Alloying Elements
Al
Cu
1. Increases strength
and hardness
2. If >12% makes the
alloy brittle
3. Hot cracking tendency
4. Decreases corrosion
resistance
8

9. Role of Alloying Elements
Al
Mn
1. Increases yield and
tensile strength
2. Improves ductility
3. Good resistance to
corrosion
4. Decrease resistivity
9

10. Role of Alloying Elements
Al
Si
1. Increases tensile
strength and hardness
uptil 13% wt.
2. Decrease the hot
cracking
3. Good resistance to
corrosion
10

11. Role of Alloying Elements
Al
Mg
1. Increases strength
and hardness
2. Good resistance to
corrosion
3. Increase weldability
and machinability
11

12. Role of Alloying Elements
Al
Zn
1. Gives heat treatable
alloys when combined
with Mg
2. Increase strength and
hardness
3. Increased toughness
but susceptible to stress
corrosion cracking
12

13. ClassificationAlloy Designation System
Al
13

14. Applications 1XXX
14

15. Applications 2XXX
15

16. Applications 3XXX
16

17. Applications 4XXX
17

18. Applications 5XXX
18

19. Applications 6XXX
19

20. Applications 7XXX
20

21. Production Wrought Al Alloys
21

22. Extrusion Process
22

23. Heat Treatment Al Alloys
 Annealing Treatment
 Solution heat treatment
 Precipitation (Hardening) treatment
23

24. Before Solution Heat Treatment After Solution Heat Treatment
Heat Treatment
24

25. Heat Treatment
Al-Cu phase diagram showing three steps in precipitation hardening
25

26. Common Defects
Defect
Casting
Defects
Extrusion
Defects
Forging
Defects
Heat
Treatment
Defects
26

27. Casting Defects
Cracks Porosity
Inclusions Segregation
27

28. Cracks Types
Radial Loop TransverseCentric
28

29. Cracks 7075
29

30. Cracks 2024
30

31. Inclusions Optical Images
31

32. Inclusions SEM Images
32

33. Inclusions SEM Analysis
33

34. Inclusions Fracture surface
34

35. Inclusions Fracture surface
35

36. Extrusion Defects
Extrusion
tears/ cracks
Scratches
Fish scaling
Un-even wall
thickness
Layer
Formation
Coarse grain
ring
36

37. Drawing Defects
Scratch Bumped ring
Un-uniformity of
wall thickness
Crack
Wrinkle End break
37

38. Cracks in Extrusion Unetched form
38

39. Cracks in Extrusion T6 etched form
39

40. Heat treatment Defects
Unqualified
mechanical
properties
Over firing
Coarse grain Quenching cracks
40

41. Grain Coarsening
41

42. Control of Grain Coarsening
42

43. 43