Which property increases when iron is rapidly cooled during quenching?

💡 Explanation

The hardness of martensitic steel increases because rapid cooling inhibits carbon diffusion, therefore trapping carbon within the iron lattice which impedes dislocation movement, rather than forming softer phases like pearlite under slow cooling.

• Which problem arose when early Islamic astronomers used geometric optics principles on astrolabes with highly reflective metal surfaces?
• Which structural concern challenged the design of stacked defensive walls around medieval castels and cities?
• Which outcome occurs when calibrating a medieval Islamic astrolabe using Polaris near the celestial pole?
• Which observational error increases when selecting distant stars on an historical astrolabe?
• Which structural vulnerability was exploited during Roman siege of a walled city using mining techniques?
• Which risk increased for opposing siege forces during the Punic Wars after the Romans adopted 'opus africanum' in their fortifications?