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Steel microstructures and hardness ranking Among common steel microstructures (pearlite, ferrite, cementite, martensite), which one gives the highest hardness under typical heat-treatment conditions? Choose the correct option.

Difficulty: Easy

Pearlite
Ferrite
Cementite
Martensite

Correct Answer: Martensite

Explanation:

Concept
Martensite (formed by rapid quenching of austenite) is a supersaturated, body-centered tetragonal phase that is the hardest common steel microstructure. Ferrite is soft and ductile; pearlite is intermediate; cementite is a hard carbide but occurs as a constituent—bulk martensite provides the highest macroscopic hardness in heat-treated steels.

Final Answer
Martensite

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