Alloy Series Main Alloy Elements
1xx.x minimum 99.000% aluminum
2xx.x copper
3xx.x silicon plus copper and/or magnesium
4xx.x silicon
5xx.x Magnesium
6xx.x unused series
7xx.x zinc
8xx.x Tin
9xx.x Other elements
The second and third numbers (xXX.x) are arbitrary numbers used to designate a specific alloy in the series. The number after the decimal point indicates whether the alloy is a casting (.0) or an ingot (.1 or .2). Capital letter prefixes indicate modifications to a specific alloy.
