L128/RZ5 datasheet
Magnesium Casting Alloy

This Alloy Conforms To BS BS LM4 . BS1490:1988
Chemical Composition
  Min Max
Rare Earth Metals 0.8 1.7
Zinc 3.5 5.0
Zirconium 0.4 1.0
Manganese   0.15
Copper   0.03
Silicon   0.01
Iron   0.01
Nickel   0.005
Magnesium 0.1 Remainder

Heat Treatment
(All Temperatures in Degrees Centigrade)
Heat to a temperature not exceeding 375 for not less than 2 hours, then air cool.

Mechanical Properties
Test values specified for requirements of British Standard L101 and shall not be less than the following values.
0.2% Proof Stress (N/mm²) 135  
Tensile Stress (N/mm²) 200  
Elongation (%) 3  
Brinell Hardness 60-80  
Shear Strength (N/MM2) 150  
Physical Properties
Specific Gravity 1.81  
Coefficient of thermal expansion 27.1 x 10 K  
Thermal Conductivity 109 Wm K  
Specific Heat 960 Jkg K  
Electrical Resistivity 68 nWm  
(Add the missing values i.e. N/mm squared, 10 to –6 K to –1, Wm to –1 K to –1, Jkg to –1 K to –1)