Question

Which of the following has the lowest tensile strength?

• A. Cementite
• B. Bainite
• C. Martensite
• D. Ferrite

Hint:

Remember: Ferrite is soft and ductile, while martensite and bainite are much stronger due to carbon content and transformation mechanisms.

Answer 1

The Correct Option is D

Ferrite (\( \alpha \)-iron) is a relatively soft and ductile phase of iron with a body-centered cubic (BCC) structure. It contains very little carbon and is known for: - High ductility - Magnetic properties - Low tensile strength compared to other microstructural constituents of steel. In comparison: - Martensite is a supersaturated solid solution of carbon in iron, formed by rapid quenching, and is very hard and strong. - Bainite is stronger than ferrite due to its fine microstructure and carbon distribution. - Cementite (Fe\(_3\)C) is a hard, brittle compound with significantly higher hardness and tensile strength than ferrite. Hence, among all, ferrite has the lowest tensile strength.