which metal is very common today and which one will be most common in future. steel or aluminum
Steel is definitely most common engineering material. Aluminum is lighter and is finding increasing use in transport industry due to energy cost and global warming. It is unlikely that it will surpass steel ever in future due to higher cost. Magnesium has the potential of growing to beat both of these metals (magnesium is more abundant on earth than either aluminum or iron (steel).
aluminum will be most commonly use in the future because it is lightweight. But metal is still the most commonly used today.
I'd say it's about even now. Each metal has its advantages and disadvantages. Al is lighter than Fe so it's favored in transportation; even though Al is more expensive than Fe it pays in fuel savings. Al replaced Fe in cans because we can taste Fe more easily. In the future look for composites to obsolete both metals.
aluminum costs more to produce, but has some very good proprieties, you will likely see steel and aluminum way into the future in about the same ratios as today
Currently, steel is very cheap but bulky and lacks variability. Aluminum is a lot more expensive, is lighter (cheaper transport), and has variability in use. For the future, however, we would start to use nanoribbon. Substantially smaller than a strand of hair and substantially stronger than steel.
