{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter 9_Part_10

Chapter 9_Part_10 - In the micrograph dark areas are Fe 3 C...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
46 MSE 2090: Introduction to Materials Science Chapter 9, Phase Diagrams Development of Microstructure in Iron - Carbon alloys Microstructure depends on composition (carbon content) and heat treatment. In the discussion below we consider slow cooling in which equilibrium is maintained. Microstructure of eutectoid steel (I)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
47 MSE 2090: Introduction to Materials Science Chapter 9, Phase Diagrams When alloy of eutectoid composition (0.76 wt % C) is cooled slowly it forms perlite , a lamellar or layered structure of two phases: α -ferrite and cementite (Fe 3 C) The layers of alternating phases in pearlite are formed for the same reason as layered structure of eutectic structures: redistribution C atoms between ferrite (0.022 wt%) and cementite (6.7 wt%) by atomic diffusion. Mechanically, pearlite has properties intermediate to soft, ductile ferrite and hard, brittle cementite. Microstructure of eutectoid steel (II)
Background image of page 2