Characteristic physical properties of magnesium alloys

Property

Unit

Temperature

Magnesium alloys

AZ91

AM60

AM50

Density

kg/m³

20°C

1810

1800

1770

Liquidus temperature

°C

598

615

620

Melt-on temperature

°C

420-435

420-435

420-435

Linear expansion

um/m

20-100°C

26

26

26

Thermal conductivity

W7(k-m)

20°C

51

61

65

Electrical conductivity

MS/m

20°C

6,6

-

9,1

Mechanical properties of magnesium alloys

Property

Unit

Magnesium alloys

AZ91

AM60

AM50

Tensile strength R_m

MPa

240 (250)

225 (240)

210 (230)

Permanent elongation limit R_p02

MPa

160 (160)

130 (130)

125 (125)

Crushing yield point

MPa

160

130

125

Breaking elongation

%

3 (7)

8 (13)

10 (15)

Modulus of elasticity

GPa

45

45

45

Modulus of elasticity in shear

GPa

17

17

17

Brinell hardness

70

65

60

Impact strength Charpy, without notch

J

6 (9)

17 (18)

18 (18)

Mechanical properties of magnesium alloys with room temperature. The values in brackets show the property values for test bars cast separately.

Shearing resistance and compression resistance of die casting alloys

Material group

Shearing resistance N/mm²

Compression resistance N/mm²

Aluminium alloys

0,8 x tensile strength

1,5 x tensile strength

Zinc alloys

0,8 x tensile strength

1,5 x tensile strength

Magnesium alloys

0,5 to 0,8 x tensile strength

2,0 x tensile strength

Shearing resistance and compression resistance of die casting alloys

Further material properties of die casting alloys

Material group

E-Module kN/mm²

Coefficient of thermal expansion 20 to 100°C um

Melting range °C

Specific thermal capacity kW'S

Electrical conductivity S ° m

Thermal conductivity W

m'K

K'g

mm²

K'cm

Aluminum alloys

68... 78

20.... 24

510... 645

0,96

12... 28

0,84... 1,63

Zinc alloys

80... 85

27

380 ... 390

0,102... 0,108

15... 16

0,92 ... 1,05

Magnesium alloys

40... 45

26

470 ... 620

1

6... 10

0,50 ... 0,84

The values are reference values and depend on the composition of the alloy and on its microstructural status.

Machining of magnesium parts

From all well-known design metals, magnesium and its alloys are the easiest to machine. Advantages:

• low specific cutting forces and therefore low energy required
• high tool lives
• short chips caused by the formation of shearing chips
• high surface quality
• high cutting speeds and therefore higher forward feeds.

Magnesium alloys can be machined with higher speed and higher forward feeds than other metals. These advantages reduce the cost of machining considerably by: Lower invest in machines and tools, lower machine and working costs and less scrap.