Nov 20 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Machinability
Forming
Heat Treatment
Forging
Hot Working
Aging
Applications
Introduction
Aluminium / aluminum alloys have excellent corrosion resistance. They are sensitive to high temperatures in the range of 200 to 250°C (392 to 482°F), and could lose some of their strength. However, the strength of the Aluminium / aluminum alloys can be enhanced at subzero temperatures, making them ideal low-temperature alloys.
The Aluminium / aluminum 7049 alloy is a forging alloy. It has excellent resistance to stress corrosion cracking. The following datasheet will provide more details about the Aluminium / aluminum 7049 alloy.
Chemical Composition
The following table shows the chemical composition of the aluminium / aluminum 7049 alloy.
|
Element |
Content (%) |
|
Aluminium / aluminum, Al |
88.7 |
|
Zinc, Zn |
7.6 |
|
Magnesium, Mg |
2.5 |
|
Copper, Cu |
1.5 |
|
Chromium, Cr |
0.15 |
Physical Properties
The physical properties of the aluminium / aluminum 7049 alloy are outlined in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
2.6-2.8 g/cm3 |
0.0939-0.1011 lb/in³ |
Mechanical Properties
The mechanical properties of the aluminium / aluminum 7049 alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Elastic modulus |
70-80 Gpa |
10152-11603 ksi |
|
Poisson’s ratio |
0.33 |
0.33 |
Thermal Properties
The thermal properties of the aluminium / aluminum 7049 alloy are tabulated below.
|
Properties |
Conditions |
|
Temp |
Treatment |
|
Thermal conductivity |
154 W/mK |
25ºC/77ºF |
T73 |
Fabrication and Heat Treatment
Machinability
The machinability of the aluminium / aluminum 7049 alloy is rated as good, especially in the heat-treated state. Lubricants should be used while machining.
Forming
Formability of the aluminium / aluminum 7049 alloy is done by hot forging or hot forming.
Heat Treatment
Solution heat treatment can be performed on the aluminium / aluminum 7049 alloy at 468°C (875°F) for a certain amount of time so as to ensure complete heating. This is then followed by a water quench. The 7049 alloy can be aged after the solution heat treatment
Forging
The aluminium / aluminum 7049 alloy is forgeable from 438°C (820°F) down to 382°C (720°F).
Hot Working
The aluminium / aluminum 7049 alloy can be hot worked from 438°C (820°F) down to 382°C (720°F).
Aging
Aging or precipitation hardening can be carried out for the aluminium / aluminum 7049 alloy in a two-step heat treating process. The first step involves allowing the product to remain at room temperature, then for 24 hours at 121°C (250 °F), and finally air cooled. For the second step, a 14-h aging process at 160°C (320° F) is carried out followed by air cooling for 14 h.
Applications
The aluminium / aluminum 7049 alloy is mainly used in structural forgings, especially in the missile or aircraft industries.