It is important binary alloy. The primary structural material in every technologically advanced culture is essentially Fe – C alloy. So the study of phase diagram related to its heat treatment microstructure and mechanical properties are important.
$$L \Rightarrow \gamma+Fe_3C$$The liquid solidified to form Austenite and cementite phase.
15.The properties and various classification of steel is studied with the help phase diagram and stress- strain diagram. This signified the importance of phase diagram of Fe – C system.
It may be noted that a eutectoid invariant point exists at a composition of 0.76 wt% C and a temperature of \(727^\circ C (1341^\circ \)F). This eutectoid reaction may be represented by
Or, upon cooling, the solid \(\gamma\) phase is transformed into \(\alpha\)-iron and cementite. The eutectoid phase changes described by above equation are very important, being fundamental to the heat treatment of steels, as explained in subsequent discussions
For Ferrous alloys, iron is the prime component, but carbon as well as other alloying elements may be present. For the division of ferrous alloys based on carbon content, there are three types: iron, steel, and cast iron. Pure iron contains less than 0.008 wt% C for commercial field. In the phase diagram, it is composed almost exclusively of the ferrite phase at room temperature. The iron–carbon alloys that contain between 0.008 and 2.14 wt% C are classified as steels where the microstructure consists of both \(\alpha\) and Fe3C phases. . In practice, carbon concentrations rarely exceed 1.0 wt%. Irons are classified as ferrous alloys that contain between 2.14 and 6.70 wt% C. However, commercial cast irons normally contain less than 4.5 wt% C.
When temperature decreases to room temperature, an alloy within this composition range must pass through at least a portion of the \(\gamma\)-phase field. Though, a steel alloy may contain as much as 2.14 wt% C.
Callister, W.D and D.G Rethwisch. Material Science and Engineering. 2nd. New Delhi: Wiley India, 2014.
Lindsay, S.M. Introduction of Nanoscience . New York : Oxford University Press, 2010.
Patton, W.J. Materials in industry . New Delhi : Prentice hall of India, 1975.
Poole, C.P. and F.J. Owens. Introduction To Nanotechnology. New Delhi: Wiley India , 2006.
Raghavan, V. Material Science and Engineering. 4th . New Delhi: Pretence-Hall of India, 2003.
Tiley, R.J.D. Understanding solids: The science of Materials. Engalnd : John wiley & Sons , 2004.
1. Important points: