What is an advantage of using alloy instead of pure iron?

Answer 1

Iron as an alloy is stronger and has a higher melting point. It can also be made to be much more resistant to rust (the most resistant alloy being stainless steel). Hence it is preferred to pure iron.
Pure iron is quite brittle and very susceptible to rust. Iron alloys maintain the strength of iron and make it more malleable (less brittle) and can also make the alloy resistent to rust.

Answer 2

When iron is produced it is too brittle and soft (the layers of atoms slide over each other easily, making it easy to bend). By adding other elements and making it an alloy, the atoms cannot slide over each other because the atoms of the different metals are different sizes. This makes the metal stronger, harder, changes its appearance and makes it more resistant to corrosion. Therefore alloying iron makes it more useful.

Answer 3

alloys are stronger due to the variety of atoms sizes. smaller ones will go in between larger ones, making the structure harder to break

Answer 4

Iron alloy steel is preferred because pure iron is brittle. Iron alloy steel is much stronger than pure iron. Likewise, an alloy is more resistant than a pure metal.