Why is the solubility of carbon in austenite larger than that in ferrite?
The carbon is soluble in the FCC -fe, forming austenite; the carbon dissolves in the body centered cubic alpha -fe to form ferrite. The gap radius of BCC (0.291,0.154) and the gap radius of face centered cubic (0.225,0.414) are large.
Its properties are similar to that of pure iron, and its plasticity and toughness are good, and its strength and hardness are low. It is usually massive or flaky in steel.The austenite structure is a face centered cubic lattice with a gap radius (0.414~0.225). Because of the larger size of the lattice gap, the solubility of carbon in gamma -Fe is relatively large. It has good plasticity.
Ferrite: interstitial solution of carbon formed in alpha Fe.Austenite: interstitial solid solution formed by carbon in gamma Fe.The ferrite structure is a BCC lattice with a gap radius (0.291~0.154). Because of the smaller size of the lattice gap, the solubility of carbon in alpha -Fe is relatively small.
