Chapter 7, Problem 90A

Interpretation Introduction

Interpretation:

The two types of metal alloys needs to be compared.

Concept introduction:

When there is combination of metals or metals that are combined with one or more elements then we get alloy. The elements like gold, silver, iron, non metallic carbon, combined with other elements to give alloys. Alloys have properties which have increased strength and hardness, corrosion resistance, and has good mechanical strength. It is used in buildings, tools, automobiles, etc.

Answer to Problem 90A

Interstitial alloys gets into the spaces between the lattice points while substitutional alloys have their atoms occupy the space of the lattice points.

Explanation of Solution

The two types of alloys are interstitial alloys and substitutional alloys. In interstitial alloys, small diameter atoms like hydrogen, carbon, nitrogen, carbon gets into the spaces between the lattice points. In substitutional alloys, the atoms of new element occupies the space of the lattice points.

Interstitial alloys	Constitutional alloys
The atoms occupying the space between the lattice atoms are not same size	The atoms occupying the lattice space are of the same size.
There is no substitution of the atom	There is substitution of atom
Example is steel	Examples are Bronze, Brass

Conclusion

Interstitial alloys gets into the spaces between the lattice points while substitutional alloys have their atoms occupy the space of the lattice points.