Specifications Comparison. Silicon: 0.4 to 0.8 Iron: 0.7 Copper: 0.15 to 0.4 Manganese: 0.15 Magnesium: 0.8 to 1.2 Zinc: 0.25 Aluminum – allowance Titanium: 0.15 & Cr: 0.04 to 0.35. Material Aluminum 6061.