Question

Which type of solid solution does this figure illustrate?

(a) Interstitial solid solution

(b) Substitutional solid solution

(c) Supersaturated solution

(d) Unsaturated solution

The question was posed to me during an interview.

This interesting question is from Hume Rothery’s Rules, Types of Solid Solutions in chapter Solid Solutions & Crystallography of Engineering Material & Metallurgy

Answer 1

The correct choice is (a) Interstitial solid solution

Easiest explanation: An interstitial solid solution is one which solute atoms fit into spaces between solvent atoms. These spaces are known as interstices. In the figure, a system of carbon in FCC ϒ iron is shown.