A Magnesium Alloy Legend

Many different magnesium compound combinations make up the various magnesium alloys. The combinations are formed using a number of metals from aluminum (the most popular) to calcium and silicon. The names of the alloy combinations are not easy to read. They consist of number and letter combinations that are like Greek to the average person. Fortunately, there is pattern to the coded alloy names. Here's a quick lesson using the alloy AZ31, looking at it one character at a time.

A
The first letter in the code stands for the major element included in the alloy. The "A" in AZ31 stands for aluminum. The Magnesium Encyclopedia lists the legend for other common letter symbols as follows:

• A, aluminum


• B, bismuth


• C, copper


• D, cadmium


• E, rare earths or rare earth metals


• F, iron


• G, magnesium


• N, nickel


• P, Lead


• Q, arsenic


• R, chromium


• S, silicon


• T, tin


• Y, antimony


• Z, zinc

The magnesium part of the alloy coding is understood, unless the alloy contains only two elements in the compound. With that said, the M symbol will be in the second spot in a magnesium alloy code.

Z
The second letter in the code is the lesser element in the magnesium alloy mix. In this case, that element is zinc. The letter symbols above apply.

3
The first number listed in the code stands for the major element in the alloy. It is a percentage that is rounded to the nearest whole number, according to the Key to Metals Database. In the magnesium alloy AZ31, approximately three percent of the alloy is aluminum. The number is approximated due to the rounding.

1
The second number in the alloy name is the amount of the second major element in the alloy. Zinc makes up one percent of the alloy AZ31.

Other Coding
Additional numbers are added to represent the modifications to the alloy. The legend is as follows:

• F, fabricated


• O, annealed


• H, cold worked


• T4, solution treatment


• T5, artificial aging


• T6, treatment with a solution and then artificial aging

These codes also denote heat treatment used on the alloys or the tempering used on the metals.

The next time you find yourself face to face with a set of classification numbers describing the metallic makeup of your magnesium alloy based materials, don't panic. The key to decoding the numbers isn't difficult at all.