Iron Carbon phase diagram 1

Phases in Fe–Fe3C Phase Diagra

?? α-ferrite - solid solution of C in BCC Fe

? Stable form of iron at room temperature. The maximum solubility of C is 0.022 wt% Transforms to FCC γ-austenite at 912 °C

?? γ-austenite - solid solution of C in FCC Fe

? The maximum solubility of C is 2.14 wt %. Transforms to BCC δ-ferrite at 1395 °C Is not stable below the eutectic temperature (727 ° C) unless cooled rapidly

?? δ-ferrite solid solution of C in BCC Fe

? The same structure as α-ferrite Stable only at high T, above 1394 °C

? Melts at 1538 °C

?? Fe3C (iron carbide or cementite)

? This intermetallic compound is metastable, it remains as a compound indefinitely at room T, but decomposes (very slowly, within several years)

into α-Fe and C (graphite) at 650 - 700 °C