Jul 29 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Introduction
Magnesium alloys are normally used as cast alloys. Magnesium alloy castings can be produced by most of the traditional casting methods such as permanent, sand, semi permanent mold and shell, investment, and die-casting.
The following sections will discuss in detail about magnesium AZ81A-T4 cast alloy.
Chemical Composition
The chemical composition of magnesium AZ81A-T4 alloy is outlined in the following table.
|
Element |
Content (%) |
|
Aluminum, Al |
7.60 |
|
Zinc, Zn |
0.70 |
|
Manganese, Mn |
0.13 |
|
Magnesium, Mg |
Remainder |
Physical Properties
The physical properties of magnesium AZ81A-T4 alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
1.80 g/cm3 |
0.0650 lb/in3 |
|
Melting point |
≥ 421 °C |
≥ 790 °F |
Mechanical Properties
The following table shows mechanical properties of magnesium AZ81A-T4 alloy.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
275 MPa |
39900 psi |
|
Yield strength |
83 MPa |
12000 ksi |
|
Poisson’s ratio |
0.34 |
0.34 |
|
Elongation at break |
15% |
15% |
|
Hardness, Brinell |
55 |
55 |
|
Hardness, Knoop |
70 |
70 |
|
Hardness, Rockwell E |
66 |
66 |
|
Machinability |
100 |
100 |
Thermal Properties
The thermal properties of magnesium AZ81A-T4 alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@20-200°C/68-392°F) |
27.2 µm/m°C |
15.1 µin/in°F |
|
Thermal conductivity |
51.1 W/mK |
355 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to magnesium AZ81A-T4 alloy are as follows:
-
ASTM A276
-
ASTM A580
-
ASTM A412