A20X / 205 / AMS 4471 Aluminum Alloy


The 200-Series of Aluminum-Copper alloys, such as A201-T7, are well known for very high strength; nearly double that of the more common 300-Series of Aluminum-Silicon alloys. Although O’Fallon Casting does cast A201, the propensity of the Aluminum-Copper alloys to “Hot Tear” during solidification has limited their widespread use. The Investment Casting industry in general considers these 200-Series alloys to be “un-castable”. 

Aeromet International PLC has overcome this obstacle with development of a truly castable 200-Series alloy, A20X, widely regarded as the strongest commercially available cast aluminum alloy in the market today. The FAA added 205-T7 to the MMPDS in 2013. SAE International has issued specification AMS 4471A for the Investment Casting of 205-T7 alloy with minimum physical properties that exceed those of cast alloys A201-T7 (AMS 4229), E357-T6 (AMS 4288) and A357 (AMS 4219). OFC has tested 205-T7 and has substantiated the physical properties of AMS 4471A.

O’Fallon Casting has been licensed by Aeromet International PLC to manufacture castings from their patented A20X / 205 aluminum alloy (AMS 4471A).

In addition to its high ambient temperature properties, A20X also has outstanding Elevated Temperature Strength, Fatigue Strength and Corrosion Resistance.

The 205-T7 will challenge alloys such as D357 & E357 for use in “Structural Casting” applications. The high properties of 205-T7 will also serve as an alternative to wrought alloys for configurations that are difficult or impossible to machine.

Although it is unlikely to replace an industry standard such as A356 in “everyday applications”, 205-T7 should be considered for use in products where the strength vs. weight ratio is a crucial consideration such as in Aerospace & Transportation.

Potential Customers will want to “Qualify” 205-T7 for use in their products and O’Fallon Casting is interested in working with partners to help develop new designs for the alloy.

For further information, contact O’Fallon Casting.