Lightweight Alloys

The vast majority of magnesium die cast automobile parts produced by Meridian Lightweight Technologies are made from three different magnesium alloys. Each is formulated to achieve a unique set of properties and performance characteristics best suited to specific applications. They are:
- AZ91D: Most commonly used alloy for high pressure die casting. Offers excellent strength to weight ratio, very good corrosion resistance and superior castability. This alloy is typically used for power train and mechanical components where toughness is more important than deformation capability.
- AM60B: Commonly used for die casting automotive safety components such as instrument panel structures and seat frames. This alloy offers excellent ductility, energy absorbing properties, strength and castability.
- AM50A: With a lower aluminum content than AM60B this alloy offers a further increase in ductility but at a slightly reduced strength and a slight reduction in castability. It is typically used where the performance requirements demand elongation properties beyond that of AM60B.
Materials Properties Chart
Mechanical Properties | AZ91D | AM50A | AM60B |
---|---|---|---|
Ultimate Tensile Strength (Mpa) | 240 | 210 | 225 |
Yield Strength (Mpa) | 160 | 125 | 130 |
Elongation % ub 2 in (51mm) | 3 | 10 | 8 |
Hardness (Brinell) | 70 | 60 | 65 |
Elastic Modulus (Gpa) | 45 | 45 | 45 |
Charpy Impact (unnotched) (J) | 6 | 18 | 17 |
Physical Properties | AZ91D | AM50A | AM60B |
Density (g/cm3) | 1.81 | 1.77 | 1.80 |
Melting Range (°F) | 815-1108 | 815-1138 | 815-1139 |
Melting Range (°C) | 435-598 | 415-620 | 435-615 |
Specific Heat (kJ/kg k) | 1.02 | 1.02 | 1.02 |
Coefficient of Thermal Expansion (um/m-k) | 26.0 | 26.0 | 26.0 |
Thermal Conductivity (W/m-k) | 51 | 65 | 61 |
Electrical Conductivity (MS/m) | 6.60 | 9.10 | nm |
Corrosion Rate (mg/cm2/day | 0.05 | 0.10 | 0.09 |
Sources: Hydro Magnesium September 2005, ASM Handbook; Magnesium & Magnesium Alloys, Dead Sea Magnesium, Noranda Magnesium Data | The mechanical properties of a die cast alloy depend strongly on the fabrication variables involved, as well as on the alloy composition. *Hydro Magnesium nm: not measured
Specialty alloys for specific applications
For applications such as power-train components where the operating temperature is above 120°C, such as automatic transmission housings, there are a number of magnesium alloys available. These alloys are designed to operate in the higher temperatures without "creep" so that bolt tension and sealing surface flatness is maintained. Meridian recommends discussing this with our engineering group to review the options available.
For complete details of the materials properties of Meridian die cast alloys, please click here.
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