Is Iron Man really made of iron?

By Leo Leung, Academic Articles, Chemistry Society, SS, HKUSU | February 29

Many of you must have imagined flying in the sky with your own battle suit. But if you are using iron to make an “Iron Man”, I am afraid it is not possible. If Iron Man need to fly, the suit need to be light and strong. However, iron is very dense and heavy, and it will rust easily. In other words, it is not possible for Iron Man to fly if the suit is made of iron. So what is Iron Man really made of?

1.Nickel-titanium
 Nickel-titanium, also named as Nitinol, is an alloy which is strong, light and has high resistance to heat. It also has super elasticity, which is approximately 10 to 30 times more elastic than ordinary metals. But the most amazing part of this alloy is its
shape memory effect.
It can retain and change its shape back to original upon heating with temperature higher than the transformation temperature. So when the suit is damaged or deformed, strong heat can heal the suit.

 

 

2. Carbon-carbon composite
 It is a type of carbon-fiber-reinforced graphite. It consists of a matrix of pure carbon to which carbon or graphite fibers of only a few µm diameter are added. This material is good at resisting high temperature (up to 2700oC) and it has very low density (1.6–1.98 g/cm3). That is why not only the Iron Man use this kind of material, but also in aerospace engineering. For instance, Boeing 787 has half of its airframe made of carbon-carbon composite.

 

3. Single-crystal titanium
 It is stronger than ordinary titanium. The crystal lattice of the single-crystal titanium is continuous and unbroken to the edges of the sample, with no grain boundaries. This feature has let single-crystal titanium to be considerable to form alloy and higher resistance to heat.
              

To conclude, material for Iron Man or flying objects must be strong and light. Iron is not suitable but nickel-titanium, carbon-carbon composite and single-crystal titanium may be your choice to made one of the flying suit!