Fe, C 1.0 (wt%), hypereutectoid alloy
Processing: Normalised [...] Sample preparation: Etched in 3% nital Technique: Reflected light microscopy / Scanning electron microscopy (SEM) Length bar: 400 μm / 40 µm / 50 µm / 10 µm Further information: This is a hypereutectoid alloy and illustrates the effect of a fast cooling rate on the resultant microstructure. The first phase to form from the austenite is proeutectoid cementite. With faster cooling there is less time for carbon to diffuse and the microstructure is more refined and may form the initial cementite as Widmanstätten side plates. / This secondary electron SEM image shows the cementite delineating prior austenite grain boundaries with a thin layer. The amount of proeutectoid phase is very low, with the majority of the area being taken by the pearlite eutectoid. Again each pearlite cell has a different orientation with the ferrite phase being selectively etched. Contributor: Prof T W Clyne Organisation: Department of Materials Science and Metallurgy, University of Cambridge
Sources: ( 1 ) ( 2 ) ( 3 ) ( 4 )