Physical Metallurgy - Understanding on Construction and interpretation of phase diagrams

A: A lines up with the Fe–C lever rule and kinetics; slower cooling lets ferrite grow and pearlite lamellae thicken. B confuses quench behavior with slow cooling. C matches hypereutectoid behavior, not 0.35% C. D misreads diffusion; retained austenite is a fast-cooling issue here.

A: A is the purpose of a tie line at the eutectoid isotherm. B pulls in heat-treatment effects not on the diagram. C drags in TTT/CCT data that isn’t shown. D confuses solid-state transformation with freezing range.

A: A matches time and temperature on the Fe–Cr–Ni diagram and explains loss of toughness. B needs hydrogen ingress, not present. C explains corrosion risk more than sudden cracking under load. D doesn’t apply without high-temperature solidification history.

A: A follows the Al–Si diagram once you move hypereutectic. B is the hypoeutectic side. C flips the temperature trend. D ignores the point nature of the eutectic.