Question

Identify the type of defect from following in stainless steel.

• A. Substitutional impurity defect
• B. Interstitial impurity defect
• C. Metal excess defect
• D. Frenkel defect

Hint:

Brass, Bronze, and Stainless Steel are classic examples of Substitutional alloys. Steel (Iron + Carbon) is Interstitial because Carbon is tiny.

Answer 1

The Correct Option is A

Step 1: Concept
Alloys like stainless steel are formed by adding impurity atoms to a host metal.

Step 2: Meaning
A substitutional defect occurs when an impurity atom replaces a host atom at its lattice site. An interstitial defect occurs when an impurity atom fits into the small spaces between host atoms.

Step 3: Analysis
Stainless steel is primarily iron (Fe) where some iron atoms are replaced by Chromium (Cr) and Nickel (Ni) atoms. Since these atoms have similar sizes to Iron, they substitute Iron in the lattice.

Step 4: Conclusion
This is classified as a substitutional impurity defect. Final Answer: (A)