Product Code:SAE AMS4439 Title:Magnesium Alloy Castings, 4.2Zn - 1.2 Rare Earths - 0.70Zr (ZE41A-T5), Precipitation Heat Treated Issuing Committee:Ams D Nonferrous Alloys Committee Scope: his specification covers a magnesium alloy in the form of castings. Rationale: his specification covers a magnesium alloy in the form of castings.