Phases in "Iron - Carbon" alloys / Ferrite, Austenite and Cementite

Playlist "Materials science"
   • Materials Science  

Alloys of the "iron - carbon" system - steels and cast irons have three main phases, i.e. structural components:
Ferrite, which got its name from the Latin word "Ferrum" - iron. The mechanical properties of Ferrite are close to those of technically pure iron. Ferrite is relatively soft, plastic and highly ferromagnetic at temperatures below 768-770 °C. Under the microscope, Ferrite grains have a light shade;
Austenite, which got its name in honor of the English scientist Robert Austen, who studied the structural characteristics of alloys of the "iron-carbon" system. Austenite is non-magnetic and has low mechanical characteristics. Its grains under the microscope also have a light shade, but different from the Ferrite grains;
Cementite, which is iron carbide with the formula Fe3C. Carbon concentration in Cementite is 6.67 %. The crystal structure of iron carbide is more complexed in comparison with the crystal structures of Ferrite and Austenite. Cementite has high hardness, comparable only to diamond, but extremely low ductility.