The material. Aluminum was once so rare and precious that the Emperor Napoleon III of France had a set of cutlery made from it that cost him more than silver. But that was 1860; today, nearly 150 years later, aluminum spoons are things you throw away—a testament to our ability to be both technically creative and wasteful. Aluminum, the first of the "light alloys" (with magnesium and titanium), is the third most abundant metal in the Earth’s crust (after iron and silicon), but extracting it costs much energy. It has grown to be the second most important metal in the economy (steel comes first) and the mainstay of the aerospace industry.
Composition
Al + alloying elements, e. g., Mg, Mn, Cr, Cu, Zn, Zr, Li
|
General properties |
|||
|
Density |
2500 – |
2900 |
kg/m3 |
|
Price |
2.5 – |
2.8 |
USD/kg |
|
Mechanical properties |
|||
|
Young’s modulus |
68 – |
82 |
GPa |
|
Yield strength (elastic limit) |
30 – |
550 |
MPa |
|
Tensile strength |
58 – |
550 |
MPa |
|
Elongation |
1 – |
44% |
|
|
Hardness—Vickers |
12 – |
150 |
HV |
|
Fatigue strength at 107 cycles |
22 – |
160 |
MPa |
|
Fracture toughness |
22 – |
35 |
MPa. m1/2 |
|
Thermal properties |
|||
|
Melting point |
495 – |
640 |
°C |
|
Service temperature |
120 – |
200 |
°C Maximum |
|
Thermal conductor or insulator? |
Good conductor |
||
|
Thermal conductivity |
76 – |
240 |
W/m. K |
|
Specific heat capacity |
860 – |
990 |
J/kg. K |
|
Thermal expansion coefficient |
21 – |
24 |
p, strain/°C |
|
Electrical properties |
|||
|
Electrical conductor or insulator? |
Good conductor |
||
|
Electrical resistivity |
2.5 – |
6 |
puhm. cm |
Cast and wrought aluminum alloys, examples of the wide range of properties of this, the most widely used light alloy.
|
Ecoproperties: material |
|||
|
Annual world production |
33 X 106 – |
34 X 106 |
tonne/yr |
|
Reserves |
20 X 109 – |
2.2 X 109 |
tonne |
|
Embodied energy, primary production |
200 – |
240 |
MJ/kg |
|
CO2 footprint, primary production |
11 – |
13 |
kg/kg |
|
Water usage |
*125 – |
375 |
l/kg |
|
Eco-indicator |
740 – |
820 |
millipoints/kg |
|
Ecoproperties: processing |
|||
|
Casting energy |
*2.4 – |
2.9 |
MJ/kg |
|
Casting CO2 footprint |
*0.14 – |
0.17 |
kg/kg |
|
Deformation processing energy |
*2.4 – |
2.9 |
MJ/kg |
|
Deformation processing CO2 footprint |
*0.19 – |
0.23 |
kg/kg |
|
Recycling |
|||
|
Embodied energy, recycling |
18 – |
21 |
MJ/kg |
|
CO2 footprint, recycling |
1.1 – |
1.2 |
kg/kg |
|
Recycle fraction in current supply |
33 – |
55 |
% |
Typical uses. Aerospace engineering; automotive engineering—pistons, clutch housings, exhaust manifolds; sports equipment such as golf clubs and bicycles; die-cast chassis for household and electronic products; siding for buildings; reflecting coatings for mirrors; foil for containers and packaging; beverage cans; electrical and thermal conductors.
