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

DoITPoMS Micrograph Library Micrograph 605 and full record

Micrograph 605 and full record

Link to image file for micrograph 605
Micrograph no
605
Brief description
Fracture surface formed by hot tearing (solidification cracking)
Keywords
alloy Link to MATTER Glossary entry for alloy, dendrite Link to MATTER Glossary entry for dendrite, hot tearing, metal, solidification cracking
Categories
Fracture, Metal or alloy
System
Al
Composition
Commercial purity (99.5%)
Standard codes
Reaction
N/A
Processing
Specimen was cast into a 'dog-bone' mould, with a heated central region. Mould constraint during solidification set up tensile stresses which caused cracking in the central region while it was still partially liquid. The dendrite surfaces are smooth because they were separated by liquid films when cracking occurred. The plastically deformed necks were points where the liquid films were bridged at the time of separation.
Applications
Sample preparation
Fracture surface
Technique
Scanning electron microscopy (SEM)
Length bar
40 μm
Further information
Solidification cracking (hot tearing) is a significant problem when casting various alloys, particularly highly alloyed compositions with a relatively large freezing range. Impurities which lead to low melting point segregates can also cause this problem.
Contributor
Prof T W Clyne
Organisation
Department of Materials Science and Metallurgy, University of Cambridge
Date
03/10/02
Licence for re-use
Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales

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