eli5, what makes steel so strong?


eli5, what makes steel so strong?

In: 7

Iron, like most metals, forms a regular crystal structure. The structure it happens to form allows the atoms to slide past one another relatively easily. When carbon atoms dissolve into the structure of the iron, they block the atoms from easily sliding, which makes the material harder to stretch or pull apart. You can think of them almost like a bunch of little velcro clips within the crystal structure, “hooking” onto iron atoms and preventing them from moving within it.

Iron (the atom) alloys (different molecules of different atoms mixed together) have internal crystals (the way those molecules bond together) that are strong in bond but very flexible in shape, and can slide onto each-other without breaking the bond.

Average rock is harder than average steel but shatters with shocks. Th’s because it’s not flexible enough, as soon as the impact displaces a molecule, the molecule separates forever from the structure, with a big enough impact you can have the entire thing breaking in half, you just need to make multiple molecules slide off their position.

Wood is more resilient and flexible than steel, but does not have bonds strong enough to give it the strength of steel. You can rip molecules apart with ease compared to steel molecules.

About sheer “strenght” which is not a real term for material propertits: Steel is not a super material, but its basic ingredients are very abundant (iron and carbon), it’s also one of the most cost effective material, being pretty cheap for what it does. Steel also has a fantastic trade off of properties, making it a good spring, structural element both in compression and tension, has an elastic module that makes it flex enough to do certain job but it’s stiff enough to do other jobs; also is a decent electric conductor. And last steel can be tuned a lot in its alloy, you can have families and families of different steel with a wide range of performances.

There are a lot of better materials around, but happen to be more expensive.