Real Materials

Interphase Boundaries

� Interphase boundaries separate materials of different composition. Boundaries of this type occur frequently in technical materials.
� In carbon steels, alloys between iron and carbon, Pearlite is a common room temperature constituent of the alloy.
� Pearlite has two constituents, ferrite and iron carbide. Ferrite is an iron/carbon solid solution and the carbide a distinct chemical compound, Fe₃C. In the photograph the carbide is dark. (x 2500)

From: Guy,
"Introduction to Materials Science," McGraw Hill (1972)

� The right hand gray region in the photograph is Austenite, an fcc solid solution of carbon in iron. The pearlite is growing from the Austenite phase.