Dependence of properties on: crystal structure and carbon content

The two important factors which affect properties of any ferrous material are:
1. its crystal structure
2. its carbon content

Knowing the effects of these two factors on material properties is highly recommended.

Properties linked with different crystal structures:

BCC structure makes: hard + strong

FCC structure makes: ductile + soft

HCP structure makes: brittle

Properties linked with carbon content:

Adding carbon to iron can improve its mechanical properties. Whatever ferrous metals we use in practical lives, almost each of them has carbon. The amount of carbon being added may vary. Other elements are also added to impart different properties but carbon is always a prime alloying element. Adding carbon to iron bring out these changes:

1. Yield strength is increased
2. Ultimate tensile strength is increased
3. Increase brittleness
4. Amount of plastic strain at fracture is reduced
5. Ductility reduced
6. Malleability reduced
7. Reduction in melting point

There is a detailed explanation behind each of these changes in properties which I am not discussing in this article. I would recommend to keep them in mind as it can fetch you some easy marks in GATE/ESE.