Designing with Magnesium
It is frequently possible to take full advantage of the lower density of magnesium due to deliberate oversize by design to include features such as lugs and flanges. These considerations negate the need to proportionally stiffen magnesium components as compared with those made from alloys with a higher modulus.
A magnesium section is about 22% as stiff as steel of the same thickness but if the depth of the magnesium section is increased to twice that of the steel then the magnesium section will be 70% more rigid and yet only weigh half as much.
Similarly, on the basis of equal rigidity, a magnesium section need weigh only 75% of the aluminium one, or when compared on the basis of equal weight the magnesium will be twice as stiff.