Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Micrograph 389 and full record

Micrograph 389 and full record

Link to image file for micrograph 389
Micrograph no
389
Brief description
Silal
Keywords
alloy Link to MATTER Glossary entry for alloy, carbon, grey cast iron Link to MATTER Glossary entry for grey cast iron, iron, metal, silal
Categories
Metal or alloy
System
Fe-C-X   Link to phase diagram
Composition
Fe, C 2.10, Si 5.60, Mn 0.50 (wt%) (Silal)
Standard codes
Reaction
Processing
Sand cast
Applications
Sample preparation
Nital
Technique
Reflected light microscopy
Length bar
100 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
Dr R F Cochrane
Organisation
Department of Materials, University of Leeds
Date
04/09/02
Licence for re-use
Attribution-NonCommercial-ShareAlike 4.0 International
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