Originally Posted by
Hector
however, Al is 3 times more expensive than steel depending on its alloy composition, heat treatment and other mechanical properties. (Call BMA and you'll find out that the Al control arm is almost twice that of steel.) There are tons of Al alloys and tons of steel alloys out of the wazoo in today's metal market. The thing about Al is that when compared with steel, ounce for ounce, it is stronger, and therefore not much Al is needed to make a rigid part. Many have the notion that steel is stronger than Al because it weighs more. This is a taboo.
The modulus of elasticity of Al, on average, is 3 times lower than steel. EDIT: [This means that Al doesn't flex as much as steel (i.e., oz for oz,) however, Al expands twice as much.] Both materials have major benefits depending on the application for their use.