AM50 Magnesium Die Casting | Ductile Mg Alloy

AM50 (AM50A per ASTM B94) trades a portion of AZ91D's strength for three to four times the ductility. With 10 to 15% elongation and superior impact energy absorption, AM50 is the magnesium grade specified for parts that must deform rather than crack - automotive safety structures, seat frames, and handheld device housings that survive drops.

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AM50 Chemical Composition

Element	Nominal %	Range
Aluminum (Al)	5.0	4.4 to 5.4
Manganese (Mn)	0.3	0.26 to 0.6
Zinc (Zn)	-	0.22 max
Silicon (Si)	-	0.10 max
Iron (Fe)	-	0.004 max
Copper (Cu)	-	0.010 max
Nickel (Ni)	-	0.002 max
Magnesium (Mg)	Balance	-

The 5% aluminum (vs AZ91D's 9%) is the whole story: less aluminum means less brittle Mg17Al12 phase, which means more ductility - and less castability and strength in return.

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Mechanical Properties vs AZ91D and AM60B

Property	AM50	AM60B	AZ91D
Tensile strength	210 MPa	225 MPa	240 MPa
Yield strength	125 MPa	130 MPa	160 MPa
Elongation	10 to 15%	6 to 8%	3%
Impact energy	High	High	Moderate
Castability	Good	Good	Best
Density	1.77 g/cm3	1.79 g/cm3	1.81 g/cm3

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Where AM50 Is the Right Call

• Automotive safety parts: steering wheel armatures, seat frames, instrument panel beams - components designed to absorb crash energy
• Handheld and portable devices: housings that must survive drop testing without cracking
• Power tool bodies: impact-prone housings and guards
• Sports and mobility equipment: frames and brackets seeing shock loads

If the part is a static enclosure or bracket with no impact requirement, AZ91D's better castability and strength usually win on cost. See the full AZ91D vs AM60B comparison for the ductile-grade landscape.

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Processing Notes

• Hot-chamber or cold-chamber: AM50 runs in both; cold-chamber is standard for larger automotive parts
• Casting temperature: close to standard AZ91D practice (melting range around 620°C), marginally higher because lower aluminum reduces fluidity
• Wall thickness: very thin-wall programs favor AZ91D - AM50's lower aluminum means slightly reduced castability and fill in thin sections
• Corrosion: same high-purity discipline as AZ91D (Fe, Ni, Cu limits) gives AM50 comparable salt-spray performance; chromate or e-coat for outdoor service

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AM50 vs AM60B - The Fine Difference

AM60B (6% aluminum) sits between AM50 and AZ91D: slightly stronger than AM50, slightly less ductile. In practice:

• Maximum ductility and impact absorption → AM50
• Balance of ductility and strength → AM60B
• Automotive OEMs often have a house preference - both are common in PPAP documentation, and KastMfg casts both

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Frequently Asked Questions

Why not always use AM50 if it is tougher?

Castability and cost. AZ91D fills thinner walls, casts faster, and is stronger as-cast. Roughly 80% of magnesium die castings are AZ91D because most parts do not need AM50's ductility.

Is AM50 weldable or heat treatable?

Neither is practical for production die castings - entrapped gas limits welding, and magnesium HPDC parts are used as-cast (F temper).

Can AM50 replace AZ91D on an existing drawing?

Usually yes mechanically (verify the strength derating), but expect slightly reduced fill on thin features due to lower fluidity. We review fill behavior at DFM before approving the switch.

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Related Magnesium Resources

• magnesium die casting - KastMfg magnesium capability
• AZ91D magnesium - the high-castability default
• AM60B magnesium - the intermediate ductile grade
• magnesium die casting applications - industry use cases

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AM50 inquiry: yaoqingpu1983@gmail.com | +86 138 1403 4409 | No.6, Rungu Road, Nanjing, China