DoITPoMS

Micrograph 71 and full record

Link to image file for micrograph 71
Micrograph no
71
Brief description
Silal
Keywords
alloy Link to MATTER Glossary entry for alloy, dendrite Link to MATTER Glossary entry for dendrite, ferrite Link to MATTER Glossary entry for ferrite, graphite Link to MATTER Glossary entry for graphite, iron, metal, silal, silicon Link to MATTER Glossary entry for silicon
Categories
Metal or alloy
System
Fe-C-X   Link to phase diagram
Composition
Fe, C 3.0, Si 6, Mn 0.7, P 0.3, S 0.1 (wt% typical) (Silal)
Standard codes
Reaction
Processing
Applications
Sample preparation
Technique
Reflected light microscopy
Length bar
80 μm
Further information
This sample shows the typical structure of silal, irons with high Si content (5.5-7.9 wt%). It is a grey cast iron alloyed with 4-6wt% Si to provide good oxidation resistance. The high Si content forms a dense, adherent iron silicate surface film, which is resistant to oxygen penetration. The flake graphite iron Silal was one of the first heat resisting cast irons developed. Spheroidal graphite Si irons have higher strength and improved ductility. The structure shows cored dendrites of ferrite with interdendritic flake graphite. A few white areas of Si carbide are also present.
Contributor
Prof T W Clyne
Organisation
Department of Materials Science and Metallurgy, University of Cambridge
Date
25/10/01
Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales
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